Observing Programmes: Galaxies

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Guaranteed Time (Key Programmes)


VNGS: Very Nearby Galaxies Survey

The Very Nearby Galaxies Survey (VNGS) is designed to probe as wide a region in galaxy parameter space as possible while maximising the achievable spatial resolution and the availability of complementary data from X-ray and optical through to radio wavelengths. The wavelengths probed by Herschel are crucial for understanding the physical processes and properties of the gas and dust in galaxies, the interplay between star formation and the gas which provides its fuel, and how these relationships change with galactic environment. Because of its focus on galaxies which are relatively bright and nearby, this survey includes many famous galaxies such as the Whirlpool galaxy (M51), a spiral galaxy with very promient spiral arms, and "the Antennae", a pair of large spiral galaxies that are in the process of merging to form a single galaxy. The sample also includes three galaxies where a massive black hole is powering an active galactic nucleus (NGC 1068, NGC 4151, and Centaurus A), two galaxies which are currently undergoing an intense burst of star formation (M82 and M83), and the closest example of an ultraluminous infrared galaxy, Arp 220, which is a remnant of a galaxy merger.

Lead Scientist: Christine Wilson (McMaster University)
UK contact: Steve Eales (University of Cardiff)

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The Interstellar Medium in Low Metallicity Environments

Much of what we have gleaned of the details of dust and gas properties and the processes of dust recycling and heating and cooling in galaxies has been limited to Galactic studies.  With Herschel we will be able to explore these issues in low metallicity dwarf galaxies, which have a deficiency in heavy elements relative to our Galaxy, and which are known by now to exhibit dust and gas properties different from galaxies like our own.  Because these objects are relatively nearby, it is possible to relate the observed variations in the brightnesses at Herschel wavelengths to the actual physical phenomena occurring within the galaxy.  This, in turn, can be extended to much more distant galaxies in the early Universe which cannot be seen in such detail. Using the SPIRE and PACS instruments on Herschel, this project is mapping the dust and gas in 51 dwarf galaxies, covering a broad range of compositions. The combination of these instruments onboard Herschel provides the first opportunity to study the dust and gas in such primordial environments, and which have not yet experienced as many cycles of star formation which creates the heavier elements. The interpretation of this data will open the door to understanding primordial conditions and star formation in the young universe.

Lead Scientist: Suzanne Madden (CEA Saclay)

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HEXGAL: the Herschel Extragalactic Key Project

The unique spectroscopic capabilities of HIFI allow astronomers to make an inventory of important atoms and molecules in nearby galaxies, and the nuclei of more distant, brighter galaxies. Such observations explore the physical conditions within regions of active star formation in a range of environments, shedding light on the physics of large scale star formation at present, and by extension in the early Universe. Key atoms and molecules include neutral and ionized atomic carbon, nitrogen, oxygen, water, and carbon monoxide. The far-infrared spectra of many galaxies reflect the balance of the gas and in regions with intense radiation.  The high spectral resolution of HIFI is unravelling the structure of the interstellar medium by analysis of the main spectral lines. In addition, water is a key molecule for our understanding of the chemistry and energy balance in the denser interstellar medium, and HIFI allows the gas temperature to be determined

Lead Scientist: Rolf Güsten (Max Planck Institut fuer Radioastronomie)

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SHINING: Survey with Herschel of the Interstellar Medium in Nearby Infrared Galaxies

The aim of SHINING is to study star formation and activity in infrared bright galaxies both nearby and at reasonable distances from the Milky Way. An important fraction of the star formation and galactic activity in the Universe takes place in such dusty, infrared bright galaxies.  The project will obtain a comprehensive view of the physics of the interstellar medium in local galaxies with a range of properties, and will be complemented by a few more distant objects, seen when more star formation was taking place.  Using PACS and SPIRE imaging and spectroscopy, SHINING is studying the physical conditions and processes in a range of galaxies, and will determine the effect of the composition of galaxies on their star formation rate, as well as study the change in galaxy activity over the recent history of the Universe.

Click here to go to the SHINING website.

Lead Scientist: Eckhard Sturm (Max Planck Institut fuer E. Physik)
UK Contact: Aprajita Verma (University of Oxford)

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Herschel Reference Survey

The "Herschel Reference Survey" will represent a benchmark study of dust in the nearby universe, producing images of a 323 galaxies at 250, 350 and 500 micron using SPIRE. The sample contains sources with distances between 45 and 75 million lightyears and are selected based on their brightness. The sample covers galaxies of all shapes and sizes, from ellipticals to spirals, and in a range of environments, from the centre of the Virgo Cluster to much more isolated locations. Overall, the Herschel Reference Survey represents the largest survey of nearby, extended, galaxies performed by Herschel and will thus represent an ideal reference for a number of other Herschel key projects focused on the more distance universe. The main goals of this survey are to investigate (i) the dust content of galaxies as a function of type, mass and environment, (ii) the connection between the dust and the other constituents of the interstellar medium and (iii) the origin and evolution of dust in galaxies.

Lead Scientist: Steve Eales (Cardiff University)

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Guaranteed Time (Round 1)


HELGA: Herschel Exploitation of Local Galaxy Andromeda

This project will make a 5.5x2.5 degree map of the Andromeda Galaxy with PACS and SPIRE, the most complete far-infrared survey of our nearest large neighbour in both area and wavelength range. By combining the Herschel data with that from other instruments, it will be possilbe to study the dust in the galaxy in unprecedented detail, including the detection of cold dust on the outskirts of the galaxy.

Lead Scientist: Jacopo Fritz (Universiteit Ghent)

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Peering into the dust: the Far-IR Emission in M31 at GMC-Resolution

Observations of the Andromeda Galaxy with SPIRE and PACS will allow the study of this large galaxy at in unprecedented detail due to both its relative proximity and the resolution of Herschel. This will allow mapping in enough detail to identify "giant molecular clouds", just 40 parsecs across. As well as providing a study of the interaction between stars and dust, this project will also be a useful calibration of the projects looking at more distant galaxies, such as KINGFISH.

Lead Scientist: Oliver Kraus (Max Planck Institut fuer Astronomie)

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HEROES:  HERschel Observations of Edge-On Spirals

Using PACS and SPIRE to observe seven large edge-on spirals, this project will look for cold dust at large galactic radii and at large heights above the plane of the galaxies.  It will also look at the variation in the dust, gas and chemical composition along the plane of the galaxies, and investigate a number of potential inconsistencies between previous observations.

Lead Scientist: Maarten Baes (Universiteit Ghent)

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[CII], [OI] and far infrared continuum emission properties of local Lyman Break Analogs

This project will observe carbon and oxygen emission from nine ultra-compact galaxies which are particularly bright in the ultraviolet.  These galaxies are local analogues for more distant galaxies known as "Lyman Break Galaxies", and will provide a useful reference for their study.

Lead Scientist: Alessandra Contursi (IPAC)

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Bright Seyfert Nuclei: FTS  spectroscopy

This project focusses on 10 "Seyfert galaxies", whose light is dominated by their galactic nuclei through accretion of matter onto supermassive black holes. These galaxies have been chosen because they are particularly bright in the far-infrared and are complementary to those of the Hercules project, the highest luminosity infrared galaxies in the local Universe. The galaxies will be studied with the SPIRE spectrometer to detect thesignature of carbon, nitrogen, water and carbon monoxide, which will help determine the interaction between the active nucleus of the galaxy and the interstellar medium.  The spectra will be complemented with images from SPIRE and PACS, and are complementary with PACS spectrometry in a related project.

Lead Scientist: Luigi Spinoglio (INAF)

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Bright Seyfert Nuclei: PACS spectroscopy

This project focusses on 10 "Seyfert galaxies", whose light is dominated by their galactic nuclei through accretion of matter onto supermassive black holes. These galaxies have been chosen because they are particularly bright in the far-infrared and are complementary to those of the Hercules project, the highest luminosity infrared galaxies in the local Universe. The galaxies will be studied with the PACS spectrometer to detect thesignature of various molecules, including hydroxyl and carbon monoxide, which will help determine the interaction between the active nucleus of the  galaxy and the interstellar medium.  The spectra will be complemented with images from SPIRE and PACS, and are complementary with SPIRE  spectrometry in a related project.

Lead Scientist: Luigi Spinoglio (INAF)

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Herschel imaging photometry of nearby Seyfert galaxies: testing the coexistence of AGN and stardust activity and the nature of the dusty torus

This project focuses on imaging nearby galaxies with very active cores, combining the Herschel far-infrared with other wavelengths from ground-based observations.  Active galactic nuclei (AGN) and starburst activities, being among the most energetic extragalactic processes, have been studied separately until the past decade, when evidence indicated that the two phenomena are related and, most frequently, coexistent. The FIR peak of cold dust emission constitutes a powerful tracer of star formation. The Herschel data, given unprecedented angular resolution and spectral coverage, will overcome the limitations of ground-based observations, allowing us to probe the cold and very cold dust components across the galaxy and even in the nuclear and circum-nuclear regions.  In addition, it will allow us to unveil the nature of the dusty torus (e.g. clumpy vs. smooth, flared disc), allowing the distinction between different theories.

Lead Scientist: Miguel Sanchez-Portal (ESAC)

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Herschel legacy of distant radio-loud AGN

This project will make images of 71 galaxies which are very bright at radio frequencies.  The galaxies, which have particularly active black holes in their cores, are seen as they were between 8 and 11 billion years ago.  It is thought that many galaxies exhibited similar behaviour in their past, and these galaxies are selected to be at the peak of their activity. By examining these galaxies at far-infrared wavelengths, it will be possible to determine relationship between the black hole, the bulge of stars around it, and the star formation in the rest of the galaxy. 

Lead Scientist: Peter Barthel (Groningen University)

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Guaranteed Time (Round 2)


Unveiling the nature of the infrared emission in M87

M87 is a giant elliptical galaxy located at the centre of the Virgo Cluster. Known to host an extremely massive black hole, it is an active galaxy showing no signs of quasar-like activity. The very nature of its infrared emission is, at present, not completely unveiled. The spectral energy distribution longward of 10 microns is dominated by the radio jet, known since more than 50 years to be powered by synchrotron emission. Whether a fraction of the infrared radiation has a different origin, such as thermal emission from a dusty torus, or from a diffuse dust component, is not clear yet.

We propose to perform deep observations of a field centered on M87 with PACS, at both 70 and 100 micron, at slow speed. In this way we will achieve the best possible spatial resolution, and the jet will be imaged at a very high sensitivity. Furthermore, we will be able to detect emission from the diffuse dust, if any, down to a few thousands solar masses.

Lead Scientist: Jacopo Fritz

Allocated time: 2.0 hours

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PACS spectroscopy of bright Seyfert galaxies in the [OIV]26um line.

This proposal is aimed at obtaining PACS spectroscopic data of 10 bright (5 type-1 and 5 type-2) Seyfert nuclei for six atomic fine-structure lines ([OIII]52um, [OI]63um, [OIII]88um, [NII]122um, [OI]145um and [CII]157um) and two molecular lines (CO J=18-17 and OH 119um). It will complete the coverage of the same ionic lines of another 11 Seyfert galaxies, already observed or reserved, by targeting the [OIII]52um line only. All targets were selected based on their optical classification and on the strength of their [OIV]25.9um fine-structure-line emission, proportional to their AGN bolometric luminosity. The proposed targets are among the brightest accretion-powered sources in the local Universe. The two [OIII] lines, together with the [OIV] line measured by Spitzer, will be used for the determination of their narrow-line-region gas density. The FIR spectroscopic tracers, combined with the MIR ones obtained with Spitzer, will enable us to classify and model the various levels of non-thermal and starburst activity in local bright Seyferts. The mid-to far-IR line ratio diagnostic diagrams that we will construct will be essential for the future interpretation of spectroscopic surveys at long wavelengths with ALMA and SPICA. The high spectral resolution of PACS will allow us to further study the dynamics of the nuclear gas, in combination with lines spectrally resolved by Spitzer IRS. The range spectroscopy with PACS has been optimized to allow the detection of 6 fine structure lines, 1 CO line, 1 OH doublet in a total time of 18.0 hours.

Lead Scientist: Luigi Spinoglio

Allocated time: 18.0 hours

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Far-infrared investigation of early-type galaxies with dust lanes

Early-type galaxies are known to harbor a complex multi-phase interstellar medium. Their dust content, however, remains mysterious. Deep optical imaging surveys have shown that a large number of early-type galaxies possess dust features in a variety of morphological forms. Dust has also been detected in emission in many early-type galaxies using IRAS, ISO and Spitzer observations. Strangely, the dust masses derived from far-infrared observations are typically an order of magnitude larger than those estimated using optical extinction features. This inconsistency in the dust energy balance could suggest the presence of a diffusely distributed dust component that is hard to notice in extinction.

We propose PACS and SPIRE imaging of a sample of 11 carefully selected, nearby early-type galaxies with regular and well-defined dust lanes. We will construct panchromatic radiative transfer models for each of these galaxies, based on multi-wavelength optical/NIR images and FIR/submm images. This will enable us to systematically investigate the dust energy balance in dust-lane early-type galaxies, to investigate the amount and the spatial distribution of the dust, to determine the optical properties of the dust, and to test the existence of a diffuse dust component.

Lead Scientist: Maarten Baes

Allocated time: 3.4 hours

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Characterizing the Molecular Outflow in Arp 220

Observations of massive molecular outflows in galaxies can significantly improve our understanding of the connection between AGN/starbursts-feedback and galaxy evolution. It is believed that the energy injection from an AGN or starbursts can quench star formation by expelling the molecular gas out of the galaxy, transforming gas-rich blue galaxies to gas-poor red galaxies. However, the evidence for massive molecular outflows had been missing, until recently, when it was discovered in Mrk231 and NGC1266.

We detected a massive molecular outflow in Arp 220 from the FTS spectrum that was observed as a part of the Very Nearby Galaxy Survey GT key project. The signature of a molecular outflow was seen in the P-Cygni profiles of OH+, H2O+ and H2O -- major molecules involved in the ion-neutral chemistry producing water in the ISM. This outflow can be driven by a hidden AGN or starburst activity in Arp 220. Because FTS could not fully resolve this outflow we were only able to provide a lower limit on the mass of the outflow and an upper limit on the velocity. To properly characterize this outflow we propose to use HIFI to fully resolve the P-Cygni line profile so that we can estimate the outflow velocity and mass with higher accuracy. We choose to observe the OH+ 972 GHz P-Cygni line profile, which is about 1000 km/s wide. To completely cover this feature and still have enough continuum to obtain a good baseline subtraction, we propose to observe it over two frequency tunings. In 2.35 hrs per frequency tuning, we will obtain a signal-to-noise ratio of about 10 and 5 per 20 km/s resolution bin in the absorption dip and the emission peak, respectively. Herschel is the only submillimeter facility that is capable of doing this observation.

Lead Scientist: Naseem Rangwala

Allocated time: 4.7 hours

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Spectral mapping of the closest galactic nucleus

Due to its proximity, our Galactic Center provides a unique opportunity to study the physical processes that occur within (extra)galactic nuclei with unprecedented sensitivity and spatial resolution. Herschel provides the only opportunity to probe the detailed physical conditions of the circumnuclear neutral material and the feedback processes with the central energy source(s) in our own Galaxy, and by extension in other galactic nuclei.

We propose to acquire wide range (51 to 670 micron) spectral maps towards the atomic and molecular gas surrounding Sagittarius A. Combining data from the PACS and SPIRE instruments, we will establish a complete inventory of the FIR spectrum accessible to Herschel across the central 5 arcmin (12 pc) of the Galaxy.

Our immediate goal is to characterize the physical and chemical conditions of the gas in both the central (ionized) cavity and in the surrounding neutral gas (often referred to as circumnuclear disk, or CND) that is presumably the reservoir of material that can flow to the central black hole. Our supporting ground-based and first targeted HIFI observations show a high-excitation state of the molecular gas in the CND, with a strong radial excitation gradient across the disk and a very sharp inner transition zone to the central cavity. These early data resemble the hard XDR-type CO line SED observed towards e.g. Mrk231.Herschel data cover lines from energy levels needed to constrain the conditions within, and energetics of the CND. We will use state-of-the-art XDR/PDR models that include multiple heating processes (a.o., shock, dissipation of turbulence) to interpret the data.

The data product will be one of Herschel's legacies in the detailed study of galactic nuclei. This data set, with high sensitivity, high spatial resolution, and broad wavelength coverage, will be an essential resource for many studies of the Galactic Center. No comparable study of this region will be possible for many years to come.

Lead Scientist: Rolf Guesten

Allocated time: 28.5 hours

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HIFI and PACS Observation of NGC 5102

NGC 5102 provides a rare opportunity to study directly the fuelling of a starburst by infalling gas. We can still see the ongoing star formation, the central extended ionized gas and the likely source of the gas in the form of the HI ring. Our Herschel programme for NGC 5102 will cover two aspects of the starburst process. First, we would like to know if there is additional current star formation hidden by dust in the inner region of the galaxy. Then, we would like to probe the dynamics and physical conditions of the molecular gas which is flowing into the centre of NGC 5102. Using the kinematic resolution of HIFI, it should be possible to measure a velocity gradient in this inflow

Lead Scientist: Sylvie Florence Beaulieu

Allocated time: 3.5 hours

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Unveiling the Warm Molecular Gas in Blue Compact Dwarf Galaxies

Hierarchical models of galaxy evolution place dwarf galaxies in the role of building blocks while on the other hand alternative models to explain galaxy "downsizing" have also been put forth. Key to the coherent picture of galaxy evolution is a proper prescription of metal enrichment and how galaxies convert their gas into stars. Our best local universe analogs to study star formation in the early universe are star forming blue compact dwarf galaxies (BCDs) with metallicities ranging as low as 1/50th that of the Sun. How these low mass, low metallicity star forming systems form stars relatively efficiently, yet with little detectable CO emission, has been a subject of much investigation over 2 decades and still remains a mystery today. Pinning down the molecular gas reservoir of two well-known star-forming low metallicity dwarf galaxies (He2-10 and IC10) is the goal of this proposal, using the SPIRE spectrometer.

Lead Scientist: Vianney Lebouteiller

Allocated time: 8.3 hours

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Open Time (Key Programmes)


Constraining the cold gas and dust in Cluster Cooling Flows

A major cosmological event is the formation of first massive galaxies, which evolve to the luminous elliptical galaxies of today. According to simulations, star formation in these galaxies was regulated and ultimately stifled by activity from the centre of the galaxy. However, the nature of these processes is open to speculation because at these enormous distances, observations provide few constraints. Similar processes occur in some nearby galaxy clusters, where star formation and cold gas is detected in and around the brightest cluster galaxies. These modern-day analogues provide us with the opportunity to understand the heating, cooling, and star formation that occur on a grand scale at greater distances. This project is determining the location and mass of the cooled gas, along with its temperature, density and other physical conditions. These new data, only possible with Herschel, are supplemented by radio, X-ray, and optical studies of the stars, hot gas, and galaxy activity. The PACS spectrometer is used to measure the emission from oxygen, nitrogen, carbon and silicon, important elements at low temperatures that also reflect the ionization state of the gas. Images from PACS and SPIRE allow the determination of dust temperatures and masses, including the detection of the coolest gas clouds. These datasets will reveal the pathway from the hot ambient medium to cool gas to star formation, a process that was widespread when the universe was young.

Lead Scientist: Alastair Edge (Durham University)

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HerM33ES: Herschel M33 Extended Survey

At a distance of 2.7 million lightyears, M33 is the only nearby, gas rich disk galaxy that allows a coherent survey at high spatial resolution. It lacks the distance ambiguity which confuses studies of our own Galaxy, and it is not as extended or inclined as the Andromeda Galaxy. M33 is a regular, mostly undisturbed spiral galaxy, as opposed to the nearer Magellanic Clouds, which are highly disturbed irregular dwarf galaxies. Observing a strip along the major axis of M33 allows astronomers to study the ionized, atomic, and molecular phases of the interstellar medium, its life cycle and thermal balance, and to  trace the formation of molecular clouds and stars. Aside from insights related to the local processes in the galaxy itself, the mapped source will set a standard, providing a basis for the interpretation of phenomena encountered in other targets of the Local Group and in more distant galaxies.

Click here to go to the HerM33ES website.

Lead Scientist: Carsten Kramer (IRAM/Granada)

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Herschel Lensing Survey

At long wavelengths, there is a fundamental limit set on the ability of Herschel to detect extremely distant galaxies.  This means that with the raw sensitivities of PACS and SPIRE, it will be difficult to reach the population of infrared-luminous galaxies at high redshifts. It is, however, possible to penetrate through these fundamental limits by taking advantage of the gravitational lensing power of intervening massive galaxy clusters.  The Herschel Lensing Survey will use PACS and SPIRE to image 40 such clusters, which have carefully been selected from the past and on-going surveys using Hubble and Spitzer. By doing this, astronomers are expecting to detect a significant number of highly magnified infrared-luminous galaxies at high redshift with PACS and SPIRE, enabling them to see further back into the history of the Universe than would otherwise be possible.  Such an extensive survey of lensing clusters will be a great legacy of Herschel, providing a large number of interesting high-redshift targets for future telescopes such as ALMA. Because of the large sample size and carefully selected clusters, this survey also offers a great potential for breakthrough discoveries such as the first detection of a "normal" galaxy in the very early Universe.

Lead Scientist: Eiichi Egami (University of Arizona)

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LoCuSS: A Legacy Survey of Galaxy Clusters at z=0.2

This project is conducting a definitive census of previously-hidden star formation in galaxy clusters at intermediate distances, and its relationship with the formation and evolution of the clusters. The sample of 32 clusters is drawn from the Local Cluster Substructure Survey (LoCuSS) for which outstanding supporting data are available, including gravitational lensing, X-ray spectro-imaging, and Spitzer maps. This unprecedented dataset on a large and unbiased cluster sample will enable astronomers to answer definitively the question: "what physical process(es) are responsible for triggering obscured star-formation in cluster galaxies?". The enduring legacy will be a study of clusters against which to compare and thus interpret the rapidly growing observations of cluster at much greater distances.

Lead Scientist: Graham Smith (University of Birmingham)

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HeViCS: Herschel Virgo Cluster Survey

Clusters of galaxies are unique laboratories for investigating the dependence of galaxy evolution on their environment. The Virgo cluster of galaxies is a relatively populous system, consisting of about 2000 cataloged members. It is the nearest galaxy cluster to our own Galaxy at a distance of about 50 million lightyears, and has been studied in a level of detail that will never be possible with more distant systems.  HeVICS is among several projects that are going to study the dust properties in nearby galaxies and the role played by dust in the star-formation cycle. The project is a wide area survey of the Virgo Cluster (about 60 deg2) using the PACS and SPIRE instruments onboard Herschel. The HeVICS survey will provide the local cluster benchmark for environmental studies and comparison with distant clusters and field surveys.

Click here to go to the HeViCS website.

Lead Scientist: Jonathan Davies (Cardiff University)

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HERITAGE: Herschel Inventory of the Agents of Galaxy Evolution in the Magellanic Clouds

The Magellanic Clouds are two very nearby dwarf galaxies, which are in orbit around our own Milky Way galaxy.  By mapping these galaxies with PACS and SPIRE, HERITAGE is providing a key insight into the life cycle of galaxies.  The far-infrared emission shows the coldest interstellar dust, the most deeply embedded young stars, and the dust ejected by older stars.  This will allow a census of the massive young proto-stars, and an inventory of the dust produced by massive stars and supernovae.  Spectroscopy using PACS maps the locations of ionised carbon, oxygen and ionised nitrogen in the galaxies, probing the warmer material.  Together, the images and spectra help constrain the physical conditions of the interstellar medium required to form stars.  By bridging the gap between studies of the Milky Way and slightly more distant galaxies, studies of the Magellanic Clouds will allow extrapolation to the early Universe.

Lead Scientist: Margaret Meixner (Space Telescope Science Institute)

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HerCULES: Herschel Comprehensive ULIRG Emission Survey

The key diagnostic of the warm star-forming molecular clouds in galaxies is provided by spectral lines from ionised carbon, oxygen and carbon monixide (CO).  While in our Galaxy the CO emission is relatively unimportant, this situation is totally different in nearby Ultra-Luminous Infrared Galaxies (ULIRGs), where the CO is an important coolant, and the thermal balance is totally different from that in our Galaxy. Since these spectral lines are very bright, they can be used to probe galaxies out to very large distances.  This project will use the SPIRE and PACS spectrometers to observe 32 galaxies, allowing inferences to be made about the infrared galaxy population in general.

Lead Scientist: Paul van der Werf (Leiden Observatory)

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KINGFISH: Key Insights on Nearby Galaxies: A Far-Infrared Survey  with Herschel

The KINGFISH project is an imaging and spectroscopic survey of 61 nearby galaxies (closer than 100 million lighyears), chosen to cover the full range of properties and local interstellar medium environments found in the local Universe. The broad goals of KINGFISH are to characterize the interstellar media of present-day galaxies, the heating and cooling of their gaseous and dust components, and to better understand the physical processes linking star formation to the ISM. KINGFISH will also provide the Herschel community with a comprehensive library of far-infrared imaging and spectral line maps of local galaxies and their principal infrared emitting components, all integrated with the extensive multi-wavelength dataset from the Spitzer Infrared Nearby Galaxies Survey (SINGS), the foundation sample for our project.  Principal science issues to be addressed by the KINGFISH team include the link between star-formation and the ISM, the inventory of dust and cold gas in galaxies, and the cooling of the interstellar medium.

Click here to go to the KINGFISH website.

Lead Scientist: Robert Kennicutt (University of Cambridge)

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Open Time (Round 1)


SPIRE Photometry on Lensed Quasars

Observations of different CO transitions in high-z quasars can help us to characterise the physical conditions of the star-forming gas, and improve current models of the co-evolution of star formation and SMBH growth. However, emission of the mm/submm continuum and/or CO lines with ground-based facilities has been observed only in a relatively

small number of QSOs, limiting our current knowledge of the dust and molecular gas properties of this important objects. We propose a low cost, high-return 10 hour detection experiment that will deliver SPIRE photometry in 3 bands for 103 targets with 0.45 < z < 4.8 (all currently known optical/radio selected QSOs lensed by foreground galaxies) as first step towards building candidate list for follow up studies.

Lead Scientist: Alicia Berciano Alba

Allocated time: 10 hours

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Origin of massive outer gas reservoirs in early-type galaxies

A surprising number (~50%) of field early-type galaxies (E and S0s) contain a cool interstellar medium phase detected through the 21cm hyperfine transition of neutral hydrogen. In some cases, this gas is distributed in extremely extensive outer distributions of up to a few 10^9 solar masses of HI. The origin and relation of such outer gas reservoirs to their host early-type galaxies is currently unknown. The gas may be directly accreted from the IGM, stripped during a tidal interaction, or acquired during a gas-rich merger. Alternatively, such gas may have been long associated with the early-type galaxy, not being exhausted due to a low star formation efficiency. In each of these cases the gas is expected to have a different enrichment history and thus a different present-day metallicity and dust-to-gas ratio. With Herschel PACS and SPIRE photometry, we propose to measure dust masses in the outer HI distributions of 15 nearby early-type galaxies. With interferometric HI data already in hand, we can then calculate dust-to-gas ratios and constrain the origin of such gas. The sample size and variety of HI masses, radial extents and morphologies will let us test if the dust-to-gas ratios vary among the sample in a way described best by a single accretion scenario. Additionally, the temperature derived for the dust in the outer gas will let us constrain the possible heating sources for the dust. In some sample galaxies, coincident UV emission suggests young stars are present. If heating from these young stars is important, we expect a variation of dust temperature in systems with and without UV emission.

Lead Scientist: Alison Crocker

Allocated time: 24 hours

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A definitive Herschel study of the most powerful local radio galaxy - Cygnus A

Powerful radio galaxies have played a central role in our understanding of active galaxies over the past five decades. Cygnus-A, the brightest and most nearby FR-II source, has been a "Rosetta Stone" in this study. It appears to have the outward characteristics of a normal radio galaxy but it's proximity allows us to identify the more subtle properties of an obscured quasar. The energy provided by this very active galaxy is sufficient to launch the energetic jets we observe but the transport of the energy to the hotspots is poorly constrained and understood. The growing realisation that AGN directly affect their host galaxy through a direct feedback mechanism throughout the lifetime of the galaxy makes it especially important for the most nearby obscured quasar to be observed with the widest possible spectral coverage. We propose to use Herschel to reveal the heating of the central region and the energetics of the hotspots. We request observations of the atomic cooling lines [OI], [OIII] and [CII] that will allow us to compare the energetics of the ISM in Cygnus A with other local and more distant galaxies.

Lead Scientist: Alastair Edge

Allocated time: 5.9 hours

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Search for dust emission from circumstellar dust in Type Ia supernovae

We propose a pilot program to investigate the nature of the non-standard extinction law of Type Ia supernovae through sub-mm observations near the supernova lightcurve maximum. If scattering and absorption by circumstellar dust contributes to the observed extinction, dust emission at sub-mm wavelengths is expected. Thus, we plan to target nearby reddened Type Ia supernovae around peak luminosity. A detection of sub-mm emission from the supernova location would dramatically improve our understanding of the processes behind the dimming of supernovae, with far reaching implications for their use as distance indicators in cosmology.

Lead Scientist: Ariel Goobar

Allocated time: 12 hours

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Dust-Based Molecular Gas Maps of Nearby Low-Metallicity Galaxies

We propose deep PACS 100 and 160 micron imaging of three nearby, star-forming, low metallicity galaxies. These data will allow us to make sensitive, high-resolution estimates of dust mass. We will combine these measurements with our in-hand HI maps to measure the dust-to-gas ratio and estimate the molecular gas (H2) content in each galaxy. This is a challenging measurement that requires requires the resolution of PACS and good sensitivity, but H2 masses at low metallicity are very difficult to estimate by any other means. We will use these H2 measurements to test recent models of H2 formation in galaxies, improve the calibration of the CO-to-H2 conversion factor, and assess the efficiency of star formation from H2 at low metallicity. We will also be able to put constraints on the life cycle of dust at low metallicity from gradients in the dust-to-gas ratio. These are all open questions that can best be addressed by observing the molecular gas in low metallicity galaxies. Carrying out such an experiment outside the Local Group is necessary something that only Herschel can do.

Lead Scientist: Adam Leroy

Allocated time: 20.1 hours

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Probing the Interstellar Medium Conditions in High Redshift Starburst Galaxies

Far-infrared and submillimeter emission lines trace the massive gas reservoirs which fuel the increased star formation seen at high redshift. While [CII] emission at 158 microns is the dominant cooling line in galaxies and directly traces the conditions in the interstellar medium, only a handful of studies have managed to detect CII at high redshift. We propose to double the number of published high redshift [CII] detections by observing 4 ultra-luminous infrared galaxies at z=1.2-2.5 with the SPIRE FTS. Our sample is unique in that it already has exquisite measurements of mid-IR spectral features and CO emission ensuring that we are observing gas-rich, starburst-dominated systems. Combining the [CII] measurements with line luminosities from CO and mid-IR spectroscopy we will complete a full diagnosis of the interstellar medium in these intensely star forming systems constraining the gas density, and the strength and source of the UV radiation field. This program is an excellent way to push the limits and showcase the capabilities of the SPIRE/FTS. We request a modest allocation of 21.7 hours (5.5 hours per source) to complete this detailed study of the astrophysical conditions in high redshift ultra-luminous infrared galaxies.

Lead Scientist: Alexandra Pope

Allocated time: 21.9 hours

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Velocity resolved HIFI spectroscopy of water lines in actively starforming galaxies

Recent Herschel spectroscopy has shown that water lines can be very prominent in the submm spectra of infra-red (IR) bright galactic nuclei. Water can efficiently be excited by the IR photons of the dust continuum and via collisions of shock-heated gas in starforming regions. In the later case H2O contributes significantly to the gas cooling. So far, the relative importance of the processes driving the water excitation are largely unknown. This is mainly because the submm lines of water in extragalactic systems have only become accessible with the launch of Herschel.

Our first velocity-resolved HIFI spectroscopy of low-level water transitions in actively starforming galaxies shows that water line profiles are formed by a mix of emission and absorption features and that the line profiles strongly vary between different water transitions. This shows that a lot of information on the underlying ISM structure is imprinted on the line profiles. On the other hand this implies, that velocity resolved spectroscopy is required in order to investigate the water excitation and the underlying physical conditions of the ISM.

We here propose to observe a set of five medium and high energy water lines using HIFI in a sample of active galaxies which are representative for a wide range of nuclear environments. In conjunction with the low-level water lines form the HEXGAL GT-KP this line selection will allow us to model the water excitation in outstanding detail and to investigate the relative contribution of the water excitation channels as a function of environment, derive chemical abundances and to investigate the underlying physical parameters of the gas.

Lead Scientist: Axel Weiss

Allocated time: 63.6 hours

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New HErschel Multi-wavelength Extragalactic Survey of Edge-on Spirals (NHEMESES)

Edge-on spiral galaxies are a unique perspective on the vertical structure of spiral disks, both stars and the iconic dark dustlanes. The thickness of these dustlanes can now be resolved for the first time with Herschel in far-infrared and sub-mm emission.

Resolved far-infrared and sub-mm observations of edge-on spirals will impact on several current topics. First and foremost, these Herschel observations will settle whether or not there is a phase change in the vertical structure of the ISM with disk mass. Previously, a dramatic change in dustlane morphology was observed as in massive disks the dust collapses into a thin lane. If this is the case, the vertical balance between turbulence and gravity dictates the ISM structure and consequently star-formation and related phenomena (spiral arms, bars etc.). We specificaly target lower mass nearby edge-ons to complement existing Herschel observations of high-mass edge-on spirals. Secondly, the combined data-set, together with existing Spitzer observations, will drive the generation of spiral disk Spectral Energy Distribution models. These model how dust reprocesses starlight to thermal emission but the dust geometry remains the critical unknown. And thirdly, the observations will provide an accurate and unbiased census of the cold dusty structures occasionally seen extending out of the plane of the disk, when backlit by the stellar disk.

The proposed 10.4 hours of PACS and SPIRE observations of low- and intermediate-mass disks complement slated Herschel observations of massive edge-on spirals and existing Spitzer observations in the near- infrared.

Lead Scientist: Benne Holwerda

Allocated time: 10.3 hours

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Physical conditions in disky U/LIRGs from [C II] and [O I] spectra - low-z analogs for high-z starforming galaxies

We propose to use Herschel/PACS spectroscopy of the [C II] 158 micron and [O I] 63 micron lines to observe a sample of 16 low-redshift infrared-luminous galaxies, at log L_IR = 11.8 to 12.3 Lsolar, that are distinguished by large size and non-merger structure. These galaxies are interesting because they have high star formation rate activity spread over a large physical area, rather than concentrated into extremely dense regions as in the nucleus of a major merger, as in most local ULIRGs. They are potentially good analogs for high-redshift IR-luminous galaxies, which appear to have far-IR spectral shapes different from local ULIRGs. [C II] is a major cooling line in photo-dissociation regions and [O I] and [C II] probe the physical conditions and UV intensity in IR-emitting regions. In a few extreme lensed high-z ULIRGs where [C II] can be measured, the high-z objects have L([C II])/L(FIR) ratios that are high, more like those of local starbursts than local ULIRGs. At z>1, much of the star formation in massive galaxies is occurring at LIRG and ULIRG levels, and U/LIRGs dominate the IR luminosity density. Understanding star forming regions in high-z IR-luminous galaxies is necessary to understand the conditions in which most of the stars in massive galaxies formed. The proposed measurements of [C II] and [O I] in this local sample of high-z analogs will test the hypothesis that redshift evolution in the IR SED shape and the [C II]/FIR ratio are due to different physical conditions in high-z IR-luminous galaxies, because of the larger physical extent of the star forming area.

Lead Scientist: Benjamin Weiner

Allocated time: 9.1 hours

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Coordinated Study of Flare Emission from Sgr A*, the Closest Supermassive Black Hole

Coordinated study of flare emission from Sgr A*, the closest supermassive black hole, reveals information about the hydrodynamics, energetics, and accretion behavior of matter within the innermost ten Schwarzschild radii. We propose to use the unique capability of Herschel/SPIRE and XMM in order to characterize flare emission simultaneously at many different wavelengths, the most important of which are completely unavailable from the ground. These measurements will explore the nature of emission at the peak of the spectrum of Sgr A* and will determine the transition wavelength at which the variable emission becomes optically thin. In particular, we will test the prediction that there will be time delay between X-ray flares and the peak emission at 250, 350, and 500 microns. We will take advantage of the calibration stability of Herschel resulting from the L2 placement to detect Sgr A* in SPIRE difference images. The proposed Herschel and XMM observations form the cornerstone of a multi-wavelength campaign that includes observations in near-IR and radio wavelengths. The cross correlation of flare emission at multiple wavelengths will have far-reaching implications for testing the emission mechanism of Sgr A* and for understanding the processes of accretion onto and outflow from the closest supermassive black hole. Lastly, a long flux monitoring of Sgr A* with Herschel over long and nearly continuous baselines will characterize the fraction of time that Sgr A* is active in submm wavelengths and will provide a legacy to unravel the key properties of the best example of a low-luminosity massive black hole.

Lead Scientist: C. Darren Dowell

Allocated time: 27.5 hours

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A Complete Herschel-Spitzer Legacy Survey of the low-redshift ULIRG Population

We propose to establish a large, complete Herschel spectroscopic atlas of the low-redshift ULIRG population, via PACS/SPIRE spectroscopy of 45 local ULIRGs. Our observations will combine with existing Herschel data to complete a purely flux limited sample of 52 ULIRGs at z<0.2. This sample comprises the most well-studied low-redshift ULIRGs in existence; they all have mid-IR spectra from Spitzer in both low and high resolution mode, many have HST imaging, and about half have X-ray observations. We will measure the physical & chemical properties of the starbursts and AGN in unprecedented detail, construct new mid/far-IR diagnostic diagrams, and determine robust calibrations for key observables of ULIRGs in the distant Universe. Our program will form a cornerstone of the Herschel spectroscopic legacy, providing (1) a comprehensive database for community exploitation, (2) a firm anchor for studies of ULIRGs in the high redshift Universe, and (3) one of the most important input catalogues for ALMA. As our intention is to create an atlas for the community, we waive all proprietary rights.

Lead Scientist: Duncan Farrah

Allocated time: 250 hours

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Characterizing Molecular Clouds at Low Metallicity

Molecular gas is difficult to detect from traditional millimeter CO transitions in dwarf galaxies below a certain metallicity. Yet, there is evidence for lots of molecular H_2 in these galaxies. Fortunately, Photo-dissociation Regions are a better tracer of the molecular material in low metallicity systems. In metal-poor galaxies, PDRs dominate the molecular core where CO is found, and in the current paradigm the PDR grows and the core shrinks as metallicity decreases. Thus, we expect critical differences in the molecular clouds of dwarfs compared to spirals, with the differences becoming more extreme with lower metallicity. Yet, understanding these differences and their consequences to star formation is essential to understanding the processes that drive star formation at low metallicities. Therefore, we propose to observe the PDRs in 5 regions in 5 typical metal-poor dwarf galaxies spanning a range in oxygen abundance. We will use these observations to characterize the molecular gas, examine the correspondence between the molecular clouds and the atomic gas and star formation characteristics, and determine the characteristics of the atomic ISM that are necessary for the formation of these dense molecular clouds. We will also test the molecular cloud structure paradigm as a function of metallicity.

Lead Scientist: Deidre Hunter

Allocated time: 53.7 hours

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Herschel-GOALS: PACS and SPIRE Imaging of a Complete Sample of Local LIRGs

We propose to obtain high-quality, PACS (70, 100, 160 micron) and SPIRE (250, 360, 520 micron) images of a complete sample of 201 local (z<0.08) luminous infrared galaxies (LIRGs) from the Great Observatories All-sky LIRG Survey (GOALS). These systems are primarily interacting or merging disk galaxies undergoing enhanced star formation and AGN activity, and represent an important evolutionary phase in the lives of massive galaxies. Herschel will measure a critical wavelength range of the FIR/submm spectral energy distribution (SED), which will enable accurate determinations of bolometric luminosities, dust temperatures, IR surface brightness and star-formation rates within the GOALS targets on spatial scales of 2-5kpc. The high-resolution PACS data will better resolve binary nuclear regions, disks, and tidal bridges and tails of colliding galaxies at different interaction stages. SPIRE will probe the hidden cold component of the ISM and will constrain the total amount of gas and dust available to fuel the starburst and AGN activity. Studies of the FIR-submm SEDs will allow us to derive the relative amounts of warm and cold dust along the merger sequence. The proximity, size, and completeness of the GOALS sample makes it well suited for studying the full range of infrared properties for LIRGs as a function of dynamical age, infrared luminosity, spectral type and merger phase. Finally, this Herschel program will provide crucial statistical results for LIRGs and ULIRGs that will enable researchers to understand high- redshift infrared galaxies in the context of local, well-resolved objects.

Lead Scientist: David Sanders

Allocated time: 84.9 hours

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Comparing [CII] 158 micron Luminosities to Spectral Properties of Luminous Starburst Galaxies and AGN

Herschel PACS spectroscopy of the [CII] emission line at 158 microns is proposed for a carefully selected sample of 123 sources that already have complete low and high resolution mid-infrared spectra between 5 microns and 35 microns from the Spitzer Infrared Spectrograph, and which also have spectral energy distributions (SEDs) from IRAS and Akari photometry. [CII] 158 um is the strongest far-infrared emission line and therefore crucial to compare with other features in luminous, dusty galaxies. Sources have 0.004 < z < 0.34 and 43.0 < log L(IR) < 46.8 (erg per sec) and cover the full range of starburst galaxy and AGN classifications. Obtaining these [CII] line fluxes with PACS will allow: 1. determining how precisely [CII] luminosity measures star formation rate by comparing to PAH features and emission lines that arise in starburst galaxies; 2. determining how [CII] luminosity and equivalent width changes with starburst/AGN fraction, by comparing with strength and equivalent width of PAH and [NeII] emission arising from starbursts, and with strength of high ionization lines [NeV] and [OIV] and silicate absorption or emission arising from AGN; 3. determining how [CII] luminosity and equivalent width changes with dust temperature and bolometric luminosity, as derived from spectral energy distributions, and whether this depends on the starburst/AGN fraction. These determinations will allow interpretation of high redshift sources for which the only available diagnostics are the luminosity and equivalent width of the [CII] line and the far-infrared rest-frame SED. The total observing program requires 20.2 hours of Herschel observing time.

Lead Scientist: Daniel Weedman

Allocated time: 20.2 hours

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Constraining the nature of high redshift infrared-faint radio sources

One of the most puzzling discoveries of the Australia Telescope Large Area Survey (ATLAS) is the population of infrared-faint radio sources. While relatively bright at 1.4 and 2.3 GHz (10-20 mJy) these sources are neither seen on optical (r=25mag) nor on near- and mid-infrared (3.6-70 micron) Spitzer maps. Existing multiwavelength data, e.g. from SWIRE, suggests that these sources are high-redshift (2<5) radio-loud AGN, suffering from heavy obscuration of their optical/NIR emission. Therefore, powerful FIR re-emission is expected, but the FIR-submm maps obtained with Herschel (in the HERMES key project) are too shallow (50 mJy at 160 micron, 30 mJy at 250 micron) to detect these sources. If they are obscured high-z analogues of local templates like 3C48 the predicted 100-500 micron flux density is about 20 mJy, well detectable with Herschel. Therefore, we propose deep PACS 100+160 micron and SPIRE 250+350+500 micron maps of six representative sources, in order to determine the nature of these infrared-faint radio sources. This will provide crucial new insights on those radio-loud high redshift AGN, which cover a lower flux/luminosity range and are therefore more characteristic than the few extremely luminous high-z radio galaxies studied so far.

Lead Scientist: Enno Middelberg

Allocated time: 6.4 hours

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Measuring the physical properties of submillimeter galaxies around high redshift QSOs

We have detected strong overdensities of submillimeter galaxies (SMGs) around a sample of z~2 QSOs using SCUBA 450 and 850 micron maps. In at least one case we have proved that most of those objects are indeed at the same redshift as the QSO, and hence related to it. If the other SMGs are also related to their entral QSOs they would represent high density peaks in the density of the early Universe, where present-day massive galaxies are thought to form. However, our understanding of the origin of such emission (expected to be due to thermal emission by dust heated by star formation) is very sketchy, since we only have one or, at best, two measurements of their far infra-red/submm Spectral Energy Distribution.

Small scan maps with PACS and SPIRE on-board Herschel would provide crucial data around the expected peak of the emission for those SMGs, allowing an unambiguous determination of its spectral shape and strength, and hence proving its origin and providing accurate estimates of the physical properties of the emitting dust. This in turn can be used to quantify the star formation rates and dust masses, to understand the evolutionary status of these objects.

Additionally, the high-sensitivity Herschel maps would probe the source counts around the QSOs in hitherto unexplored bands to unprecedented depth, providing vital clues to really understand the role of these objects in the formation of galaxies in these early peaks in the density of the Universe.

Lead Scientist: F.J. Carrera

Allocated time: 2.9 hours

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Water and CO: Signatures of Microturbulent Shocks in NGC 891

We propose to detect and map rotational line emission from water and CO in the edge-on spiral galaxy, NGC 891. Both water and CO rotational lines are important coolants for low velocity C-shocks resulting from micro-turbulence in molecular clouds. The water lines are of particular interest, as they are definitive shock tracers on galactic scales. Micro-turbulent shocks are an important process through which molecular clouds dispel their turbulent kinetic energy enabling them to collapse and to form stars. NGC 891 is the ideal source for detecting shock tracers from the more quiescent ISM within a normal spiral galaxy: it is presented to us edge-on so that column densities along the line of sight are quite large, and it is nearby so that the edge-on geometry still nearly fills the Herschel spectrometer beams. The combination of high columns, and good beam match enables the detection of particularly weak lines. Our search is motivated by our recent study of NGC 891 in its H2 rotational line and [OI], [CII], and [NII] fine-structure line emission that provides strong evidence for micro-turbulent shock excitation of the S(2) and S(1) rotational lines. These lines are bright, and within C-shock models, several water lines are predicted to be nearly equally bright, and readily detectable with Herschel/PACS and HIFI, and the rotational ladder of CO is detectable with SPIRE. The proposed Herschel observations of water CO will provide the first definitive indicators of the micro-turbulent shocks that along with H2 line emission are the dominant coolants for molecular cloud interiors. Herschel is the only facility that can observe these water lines that are totally obscurred by the Earth's atmosphere even at aircraft altitudes.

Lead Scientist: Gordon Stacey

Allocated time: 22.1 hours

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Herschel study of black hole and galaxy evolution: The z<0.3 QUEST AGN sample.

We propose 15.6 hours of Herschel time to secure high quality data,over the entire 70-500 micron range, for a group of 27 local, luminous active galactic nuclei (the QUEST AGN sample). The sources represent well the optically selected PG-QSO sample with redshifts up to z=0.3, and have been investigated, in great detail, in almost all other wavelength bands. The new far infrared (FIR) data set will be ideal to study various fundamental questions related to the connection and co-evolution of AGN and their host galaxies. Our previous Spitzer/IRS work on the sample has already revealed a clear relationship between the total AGN luminosity and the star formation rate (SFR) in their hosts. However, the previously undetected FIR sources may be situated in red-and-dead hosts and the Herschel observations can find these objects and allow a direct comparison of their AGN properties, like black hole (BH) mass and accretion rate, with those of the sources with high SFR. The observations will also provide unique information about the "intrinsic infrared AGN spectrum" with consequences to dust properties and distribution in such objects. Our sample is a needed ingredient in any Herschel-based studies that combine FIR-selected (IRAS, Spitzer, Herschel) and optically selected samples with their different biases. Its later comparison with similar high redshift observations will provide invaluable information about the cosmological evolution of AGN and star forming galaxies.

Lead Scientist: Hagai Netzer

Allocated time: 15.6 hours

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Black hole growth and star formation in the early universe: the z=4.8 sample

We propose to secure Herschel PACS and SPIRE observations for a unique sample of 44 z=4.8 active galactic nuclei (AGNs). This is a genuine optically-selected flux limited sample that was observed by us from the ground thus providing reliable black hole (BH) and accretion rate estimates based on the properties of the strong MgII 2800A line. Reliable BH mass estimates at z>2 can only be obtained in narrow redshift bands at around z=2.3, z=3.3, z=4.8 and z=6.5. Our z=4.8 sample is thus a corner stone for answering any question related to galaxy and BH evolution, in particular the co-evolution (if any) of BHs and star formation (SF) in the early universe. The Herschel observations will provide invaluable information about the SF rate (SFR) in the host galaxies of the z=4.8 AGNs which, when combined with observations in the other redshift bands will trace the growth of the most massive BHs and the stellar mass in their hosts. SPIRE observations will provide SFRs (or upper limits on the SFR) in all sources. PACS observations of the more luminous sources in the sample will provide a. priors for the SPIRE observations that will allow us to go below the confusion limits and b. unique information about the 17-40 micron (rest) emission by warm (200K) dust close to the centers of these sources.

Lead Scientist: Hagai Netzer

Allocated time: 13 hours

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Ram pressure-induced shocks in stripped Virgo spirals

We propose to investigate the presence of ram pressure-induced shocks in three Virgo cluster galaxies with clear evidence for on-going ram pressure stripping, from a wealth of radio continuum, optical, infrared, and HI data. To achieve our aims, we will perform PACS spectroscopy to measure the [OI] and [CII] emission line strengths of three outer-disk regions located along the leading edge of interaction between the hot intracluster medium (ICM) and the cooler galaxy interstellar medium (ISM). The ionization state of the ISM gas within the leading edges will be revealed by the ratios of these two emission lines since they are the dominant coolants in the neutral and ionised ISM at low temperatures. Previous Spitzer IRS observations hinted at the presence of shock-excited molecular Hydrogen. Hence, these proposed PACS spectroscopy observations will provide independent confirmation of ram pressure-induced shocks in the cold ISM along the leading edges of these ram pressure-stripped galaxies. Evidence for shock excitation throughout the ISM may also explain the enhanced global radio-toratios observed in galaxies which are experiencing strong ram pressure.

Lead Scientist: Ivy Wong

Allocated time: 22 hours

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Do Ultraluminous X-Ray Sources Really Require Intermediate Mass Black Holes?

Ultraluminous X-ray sources are non-nuclear sources in normal disk galaxies that are second only to AGNs in point-source luminosity. Their X-ray luminosities exceed the Eddington limit for stellar mass black holes (15 Msun), suggesting the need for intermediate mass black holes. This inference depends on the X-ray emission being isotropic, an assumption that we test here. X-ray spectral studies show that much of the soft X-ray emission is absorbed by gas and dust, which will be reemitted isotropically in the far-infrared. The ratio of the absorbed X-ray luminosity to the FIR luminosity is a direct measure of the anisotropy of the X-ray emission. Our previous study with Spitzer, which focused on PAH emission, suggests that the X-ray emission is highly anisotropic. However, if the X-rays destroyed the PAHs, we should focus on the longer wavelength emission, where MIPS observations indicate weak detections. The limitations of the MIPS observations were the poor point spread function and short exposure time, which will be improved upon by the proposed PACS 70 um observations of three highly luminous and nearby ULXs. These data will determine whether ULXs are sub-Eddington or super-Eddington emitters.

Lead Scientist: Joel Bregman

Allocated time: 11.4 hours

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NGC 1266: Probing an extraordinary phase of galaxy evolution with Herschel

Two important, coupled questions in galaxy evolution are: how did gas-rich galaxies deplete their interstellar media to become gas poor and how do feedback mechanisms from star formation and active galactic nuclei (AGN) regulate star formation and supermassive black hole growth? Thus, observing galaxies with substantial gas content, nuclear activity, and outflows can make a significant impact on our understanding of galaxy evolution. Recently, observations of an early-type galaxy, NGC 1266, an S0 LINER, revealed a powerful molecular outflow associated with a compact (300-pc radius) and massive reservoir (of order 10^9 solar masses) of molecular gas. The outflow velocity exceeds the galaxy escape velocity, with an estimated flow of 40 solar masses per year. At this rate, the galaxy will deplete its molecular gas within 30 Myrs. There is evidence for an AGN, but the star-formation activity is weak given the gas surface density and no companion galaxy is visible. These unusual characteristics make NGC 1266 an excellent candidate for detailed study of the molecular gas with Herschel to help characterize gas depletion and feedback mechanisms in galaxies. With HIFI and the SPIRE FTS, the CO spectral lines will be measured, from J = 5 – 4 to J = 13 - 12, which, combined with detailed models of the line emission, will yield precisely the temperature, density, optical depth, and mass of the molecular gas in the core and outflow. High signal-to-noise line detections and good velocity resolution, provided by HIFI, will enable the core line emission to be robustly separated from the outflow line emission, and to study the dynamics of the outflow. With the SPIRE-FTS, a full low resolution spectral view from 450–1500 GHz will be obtained to detect tracers of dense gas, such as HCN, HCO+, and HNC. The dense fraction of the gas can be assessed and the dust continuum emission can be used to infer an independent measure of molecular gas mass. Herschel is the only facility capable of making these observations.

Lead Scientist: Jason Glenn

Allocated time: 6.3 hours

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A Population of Dusty B Stars in the SMC: The First Extragalactic Debris Disks?

Using data from the Spitzer Survey of the SMC, we have discovered a population of 120 main sequence B stars with large 24 micron excesses. Optical spectroscopy and the IRAC SEDs demonstrate that they are not ordinary YSOs or Be stars. We suggest instead that these objects may be debris disks around massive main sequence stars. Confirmation of this hypothesis would provide one of the only ways to study the process of planet formation in a low-metallicity external galaxy. We have measured the mid-IR SED of the dust emission with IRS spectroscopy and determined that both cold and warm dust is present. We now propose PACS photometry at 70 microns to unambiguously separate the dust into its warm (and therefore circumstellar) and cold (possibly interstellar) components. These data will enable us to determine how much of the dust is warm and better constrain the temperature distribution; any targets with substantial amounts of warm dust are almost certainly debris disks. If the B stars do indeed host debris disks, they provide perhaps the only plausible method for constraining planet formation in an external galaxy for the foreseeable future.

Lead Scientist: Joshua Simon

Allocated time: 9 hours

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Beyond the Peak: Resolved Far-Infrared Spectral Mapping of Nearby Galaxies with SPIRE/FTS

We propose a spatially-resolved far-infrared spectroscopic survey of a sample of 23 nuclear and extranuclear regions within 22 nearby galaxies, selected to represent the broadest range of key physical properties, including luminosity, gas and stellar mass, star-formation density, and infrared activity. Combined with our wealth of ancillary imaging and spatially resolved spectroscopy from the heritage of SINGS/KINGFISH and related surveys (ultraviolet, optical, infrared, low-J CO, and radio), the proposed SPIRE/FTS dataset will provide key insights into the processes that shape the interstellar medium and govern star formation. Detection of the continuum emission from large grains over 200-650 microns will place new constraints on the long-wavelength behavior of dust emissivity. The richness of the emission line spectrum in this wavelength regime will allow us to quantify the excitation conditions of CO over a wide range of environments, and to characterize the physical properties of warm and dense gas within galaxies on kiloparsec scales, interpreting these properties using models of photo- and X-ray-dissociated gas, and comparing directly with resolved tracers of star formation, heating, and AGN activity. With capabilities unmatched by existing or planned ground- or space-based facilities, SPIRE/FTS mapping of a well-studied sample of nearby galaxies will serve as a crucial, unique, and lasting foundation for interpreting ALMA observations of galaxies at high redshift.

Lead Scientist: J.D. Smith

Allocated time: 149.4 hours

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A benchmark study of Active Galactic Nuclei

We propose Herschel observations of a sample of 176 AGN selected over a narrow redshift range (0.9<z<1.1) but spanning 5 magnitudes in optical luminosity. This selection allows us to decouple luminosity dependent effects from evolutionary effects in a sample selected close to the peak of AGN activity. Combined with our existing multiwavelength dataset (Spitzer, XMM-Newton, SWIFT, UKIRT...) the Herschel observations will provide a benchmark for all future high-redshift AGN studies. We have three primary science goals: (1) to determine the evolutionary status of the AGN by measuring their stellar masses, black-hole masses and star-formation rates, (2) to determine how the spectral energy distributions of the AGN vary as a function of luminosity, and (3) to determine the evolutionary status of the `galaxy clusters' known to be forming around the AGN. The aims of this proposal can only be achieved with pointed observations made with the Herschel Space Observatory.

Lead Scientist: Jason Stevens

Allocated time: 55.1 hours

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A Herschel Survey of [OI]63um in 1<z<2 Submillimetre Galaxies in the ECDFS: A Bridge to ALMA

Luminous obscured galaxies likely dominate the total bolometric emission from star-formation at the early epochs of z~2-3, and are most efficiently identified through their (sub)millimetre emission and are so-called submillimetre galaxies (SMGs). The intense starbursts in SMGs are fuelled by their large observed H2 gas reservoirs, as traced by CO interferometric surveys, although the details of how their immense luminosities (L_fir>5x10^12 Lsun) and star-formation rates (~100-1000 Msun/yr) are powered are not well understood: Are SMGs just scaled up ULIRGs with star-formation occurring in a highly-obscured nuclear region (with perhaps some contribution from an AGN)? Or does the star-formation occur in a more extended, cooler component, such as in "normal" star-forming galaxies. One route to tackling this question is to construct a data set of the brightest fine-structure ISM emission lines ([CII] and [OI]) in a well-defined sample of SMGs, which with ancillary CO data, will allow us to study the physics of the ISM and its interplay with the heating source. Similar benchmark data sets are being compiled by several Herschel programs for local LIRGs and ULIRGs, which will act as a link to help interpret the high-redshift SMG observations. Here we propose a timely and systematic study with the PACS spectrometer of [OI]63um in a flux-limited sample of SMGs with secure spectroscopic redshifts between 0.7<z<2 in the ECDFS - the premier cosmological survey field for ALMA due to its southern declination and wealth of existing ancillary datasets. The combination of these Herschel data ([OI]) and future ALMA data ([CII] and CO) with state-of-the art PDR modelling will reveal new insights into the typical physical conditions of the ISM in the most active high-z star-forming population of galaxies, including the average gas temperature, density, abundance, and radiation field strength integrated over the galaxy.

Lead Scientist: Kristen Coppin

Allocated time: 26.3 hours

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Tidal Tales of Dark Gas: Searching for [CII] in CO-Deficient Star Forming Tidal Tails

How is star formation in tidal debris affected by gas properties? To probe the molecular gas properties of 3 tidal tail regions, we propose to use the PACS spectrometer on Herschel to observe the [CII] 158 micron line. Two particular tidal tail regions of interest are Clump II in the M81 group and the western tail of NGC 2782. These two regions are HI-rich and have young blue stars or star clusters detected in optical broadband and narrowband H-alpha imaging; however, observations of CO 1-0 show non-detections down to low limits. In contrast to these two regions, the base of the eastern tail of NGC 2782 is rich in HI and CO and has young star clusters. Although the non-detection of CO suggests that there is no molecular gas in Clump II and NGC 2782W, we expect the molecular gas to have a higher fraction of "dark gas" or mostly unobservable molecular hydrogen and C+. One way to observe this "dark gas" is to use the far infrared fine structure line of [CII] at 158 microns. Using these [CII] observations and previous data in optical, near-infrared, submillimeter, and radio, we will compare the measurements of gas and young stars in Clump II and NGC 2782W to those in NGC 2782E to examine the dependence of star formation in tidal tail regions on gas properties.

Lead Scientist: Karen Knierman

Allocated time: 9.4 hours

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ISM Heating and Cooling in Massive Galaxies: The Andromeda Galaxy as Fundamental Calibrator

M31, the nearest massive galaxy, affords a unique opportunity to draw up the energy balance of the star-formation (SF) process on the spatial scales (<50 pc) of individual SF regions and of the presumed SF energy deposition. For the `heating terms', UV to near-IR data from the Pan-chromatic Hubble Andromeda Treasury (PHAT) provide a direct census of all young stars in M31; for the `cooling terms', a rich set of existing multi-wavelength data (far-UV to HI) provide many of the cooling diagnostics for the gas and dust. Here we propose to obtain the crucial missing link in the overall ISM energy budget by mapping the dominant, and hence indispensable, cooling lines of the neutral medium, [CII] and [OI].n Specifically, we propose PACS [CII] and [OI] line mapping of several selected="selected" (700pc x 700pc) regions in M 31 with ongoing SF, complemented by [N II] observations. These data will enable a foundational study of the energy budget and feed-back of star formation. The data will also provide a stringent calibration of the [CII] line as a local star-formation indicator. Finally, the data set provides the opportunity to understand the sub-grid physics that is needed both for galaxy formation simulations and for interpreting the enormous wealth of gas and dust diagnostic data in more distant galaxies.

Lead Scientist: Karin Sandstrom

Allocated time: 47.1 hours

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Balancing the Energy Budget in LIRGs: A PACS Spectroscopic Survey of Luminous Infrared Galaxies in GOALS

Luminous Infrared Galaxies (LIRGs; having LIR > 10^11 Lsun), emit a significant fraction of their bolometric luminosity in the far-infrared and are a mixture of single galaxies, interacting systems and advanced mergers, exhibiting enhanced star formation rates and a higher fraction of Active Galactic Nuclei (AGN) compared to less luminous galaxies. With the Great Observatories All-sky LIRG Survey (GOALS), we are measuring the properties of a large, complete sample of 202 low-redshift LIRGs across the electromagnetic spectrum using Spitzer, HST, Chandra, GALEX and a number of ground-based observatories. Here, we propose to measure the [CII] 157.7, [OI] 63.2 and [OIII] 88 micron far-infrared emission lines and the OH 79 micron absorption feature in the GOALS sample with the PACS on the Herschel Space Observatory. We will target 154 LIRGs in [CII], [OI], and OH and 66 LIRGs in [OIII] for a total requested time of 166.9 hrs. The PACS data will allow us to penetrate the dust and measure the spatial distribution, dynamics and overall energy budgets in a large sample of LIRGs at low redshift for the first time. In addition to providing a measure of the physical conditions in the warm, neutral and ionized interstellar medium (ISM) in LIRGs, these data will allow us to establish a precise, quantitative FIR-based measure of the star formation rate that can be used across a wide range of galactic luminosities, even in the presence of powerful AGN. GOALS, with its rich ancillary dataset that covers X-ray through millimeter wavelengths, provides the perfect sample for this study. Our proposed observations will greatly extend the work started with ISO, and lay the foundation for high-redshift galactic studies with future facilities (e.g., ALMA) that will target the FIR and sub-mm spectral regions over the next decade.

Lead Scientist: Lee Armus

Allocated time: 154 hours

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Completing the PACS coverage of the Herschel Reference Survey

The Herschel Reference Survey (HRS) is a Herschel Key Program focused on the study of the interplay between dust and star formation in the local universe. The HRS represents the only volume- and magnitude-limited Herschel survey of resolved nearby galaxies, spanning the whole range of morphological types (ellipticals to late-type spirals) and environments (from the field to the center of the Virgo Cluster).

Here we propose to use Herschel to acquire PACS 100 and 160 micron maps for 235 HRS galaxies. This will complete the coverage of the HRS in the spectral range 100-500 microns, currently biased towards early-type, cluster galaxies. These data are essential to characterize the far-infrared and sub-millimetre dust spectral energy distribution (SED) and to investigate how it varies with internal properties and environment. With complete PACS coverage, the HRS will be the ideal sample for statistical studies in the FIR/submm regime at z~0 and the reference for investigations at cosmological distances. In particular, we plan to combine the Herschel observations with UV, HI, CO, optical and near-infrared data already available to investigate the interplay between the interstellar radiation field and dust, to study the effects of the environment on dust content and star formation activity, to carry out the first complete morphological study of local galaxies in the far-infrared and to provide the community with the largest catalogue of UV-to-radio continuum integrated and resolved (at a kpc scale) SED. Thanks to its selection and multi-wavelength coverage, the HRS will thus represent a legacy for galaxy studies for many decades to come.

Lead Scientist: Luca Cortese

Allocated time: 50.8 hours

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Measuring the ISM Content of a Large Volume Limited Sample of Nearby Quasars

The coevolution of central black holes (BH) and their host galaxies driven by starbursts and the feedback of AGN are major elements of recent galaxy evolution models. Here we propose to investigate these processes in a volume limited sample of PG QSOs, by examining if and how their ISM properties reflect the evolutionary stages of the host galaxy, and the mass of the central black holes. PG QSOs are ideal for such a study because there are complete and uniform data on their BH masses, X-ray to MIR SEDs, NIR and MIR spectral characteristics as well as HST imaging. As such their accretion rates are well known. Here, we request 43.2 hours of PACS and SPIRE observations to measure the full FIR SEDs for a complete sample of 87 PG-QSOs. These data will provide unique sampling of the ISM content of the hosts with measurements of the dust masses, luminosities and temperatures. For objects at the mean redshift of z = 0.2, the proposed PACS photometry will be used to constrain the mass of hot (~60 K) and cold (~25K) dust down to 3e5 and 3e7 Solar Masses respectively, that is total ISM masses similar or less than the Milky Way. As such the proposed data will provide extremely impressive measurements of (1) the ISM masses and luminosities present in the PG-QSO hosts and (2) the relative amounts of gas in high activity (hot dust -- star-formation or AGN) versus low radiation field environments. These data will provide the fundamental dataset for studies of the IR radiation from optical QSOs and understanding the host galaxy properties. The goals of this proposal mesh well with one of Herschel's main mission statements: "Unveiling hidden details of star and galaxy formation and evolution".

Lead Scientist: Luis Ho

Allocated time: 43.2 hours

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The Interstellar Medium, Star Formation and Galaxy Evolution in Early-Type Galaxies

We propose spectroscopic observations of the primary ISM cooling lines and the high-J CO ladder in a well-defined sample of nearby elliptical and lenticular galaxies. FIR line and line/continuum ratios will be used in conjunction with PDR models to constrain the physical conditions (gas density and strength of UV radiation field) in the ISM of these early-type galaxies. Similar work has been done extensively for spiral galaxies and (U)LIRGS but has only sporadically been done for quiescent ellipticals and lenticulars. We already have a broad suite of ancillary data for our targets, including HI and CO maps, high density molecular tracers, maps of the stellar populations (ages and metallicities) and optical emission lines. Our targets make an important bridge between normal star-forming spirals and cooling flow cluster galaxies, as they have some properties in common with both other types. Thus, this project is essential for placing other Herschel approved projects into the broader context of the interactions between gas and stars across the entire Hubble sequence.

Lead Scientist: Lisa Young

Allocated time: 60.7 hours

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The Impact of Quasars on their Host Galaxies: Gas Conditions and Star Formation in the Central Kiloparsec

We propose to study the impact of powerful quasars on the star-forming gas in their host galaxies' central kiloparsec with a 44-hour program using the PACS and SPIRE spectrometers. We are targeting four intrinsically luminous and gravitationally-lensed AGN systems in the z~2-4 era which show evidence of obscured star formation in their hosts. We will measure the five bright far-IR fine-structure transitions: [SiII] 35, [OI] 63, [OIII] 52 & 88, and [CII] 158 which are the dominant interstellar gas coolants in galaxies. We will combine the Herschel line fluxes with Z-Spec measurements of the peak of the CO spectrum to provide a complete census of the atomic and molecular gas mass and cooling in the central kpc of these systems. Our datasets will allow us to perform two key experiments: 1) What heats the gas in the central kpc? When compared with one another and the dust continuum, the line measurements distinguish between UV-photon heating in photo-dissociation regions (PDRs) and bulk heating due to X-rays and/or cosmic rays. Relative to the PDRs, the bulk heating sources are very efficient at heating the gas and produce strong line-to-continuum ratios as well as an enhanced [SiII] / [CII] ratio. If X-rays or cosmic rays are really an important heating source, we will see unusually strong [SiII] and [OI] in these systems. 2) Is the stellar mass function biased toward high masses in these systems? It has been proposed that bulk heating mechanisms are likely to impact the stellar IMF, boosting the characteristic mass by as much as an order of magnitude relative to the Galaxy. Our measurements of the [OIII] transitions, when compared with the far-IR continuum or [CII] which trace total star formation provide a measure of the fraction of very massive stars in the stellar IMF. Similarly, comparison of the [OIII intensities and lower-ionization species (including upper limits) probe the stellar effective temperature through comparison with nebular models.

Lead Scientist: Matt Bradford

Allocated time: 43.7 hours

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Death by Debris: Testing a new picture of Star Formation Quenching in Compact Groups

Recent studies show that compact groups appear to follow an evolutionary sequence, linked to gas depletion, caused by interactions in the dense environment. Spitzer photometry of Hickson Compact Groups show a distinctive gap in IRAC colour-colour space, suggesting rapid evolution from dusty to dust-free systems which seems to correlate with HI-depletion in the galaxies, but the mechanism responsible is poorly understood. Originally ram-pressure stripping, by analogy with clusters, was thought to be responsible, but the HI depletion is uncorrelated with the presence of hot X-ray gas. Based on our recent Spitzer spectroscopy of a sample of HCGs, we propose a new hypothesis that connects the colour evolution to the HI-depletion seen in the group galaxies. In this scenario, galaxies collide with previously stripped tidal debris, that either heats the disk ISM or strips it, thus shutting off star formation and accelerating the transition from dusty, gas-rich disks to gas-poor, dust-free systems. PACS deep [OI]63 and CII[158] maps allow us to look for smooth bow shock or clumpy shock signatures to discern between heating and stripping of the disk gas. SPIRE cold dust imaging will allow us to search for additional evidence of disk disruption and truncation. This project requires 80.6 hours of observing time.

Lead Scientist: Michelle Cluver

Allocated time: 80.6 hours

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The Herschel Legacy of powerful 3C radio galaxies and quasars at z<1

We propose Herschel observations of a complete sample of 3C radio-galaxies and quasars at redshift z<1. For all sources Spitzer mid-IR spectra are available. The aim is to quantify the orientation-dependence of AGN radiation (AGN unification), to investigate the interplay between accretion onto the central black-hole and star-formation in the hosts, and to understand the evolution of the black-hole/stellar-bulge relation. The low-frequency radio-selection provides us with powerful and massive active galaxies free from any orientation/obscuration bias, a requirement for testing AGN unification. The properties of the 3C sources are well known throughout the electromagnetic spectrum, except in the far-IR/sub-mm, where most of them were hitherto outside the capability of space missions to reach reliable measurements. We propose PACS 70-160 micron photometry of 72 sources supplemented by SPIRE 250-500 micron photometry of 11 sufficiently bright sources, in order to measure their detailed spectral energy distributions between available Spitzer and SCUBA/MAMBO data. Depending on redshift of the sources and predicted flux, the filter choice is optimised to provide best rest-frame FIR coverage. The rest-frame FIR emission serves as an isotropic calorimeter and the MIR/FIR luminosity ratio is determined by the relative strength of the AGN and star-forming contributions combined with dust obscuration. These observations will return crucial new information on the energy processes in powerful AGN and their hosts at z<1, providing an essential anchor for studies of galaxy and AGN evolution, in particular for a consistent comparison with Herschel observations of several (radio-loud) AGN samples at cosmic epochs z>1.

Lead Scientist: Martin Haas

Allocated time: 20.5 hours

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GRAPHICS: GRB Afterglow Photometry with Herschel Infrared Cameras

Gamma-ray bursts (GRBs) are the most luminous explosions in the universe. It has been difficult to obtain a full spectral picture of the phenomena in the short period when GRBs become ``alive'', i.e. when they generate bursts in Gamma-ray and produce afterglows in other wavelengths. Between NIR (12micron) and submillimeter (850micron) there lies nearly two orders of magnitude of spectral range where GRB afterglows have never been detected. Herschel is unique in its cutting edge sensitivity, efficiency, and readiness in FIR observations, and is capable of detecting GRB afterglows. Observing GRB afterglows with Herschel would greatly enrich our understanding of GRB physics and conditions of the Universe in early epochs. We propose Target of Opportunity studies using the SPIRE and PACS instruments of Herschel to observe 3 bright GRB afterglows, each within a few hours to a few tens of days after burst. We will make follow-up observations after the initial one to photometrically measure GRB light curves and IR SEDs. We will make ground optical observations to compliment Herschel data, and have the the GRB community informed. Observing the forward shock peak in the FIR light curve and compare it (both the flux and time) with those in the optical and radio bands would give a unambiguous test to the fireball model, and offer a direct measurement of the density profile of the circumburst material. Catching the short-lived reverse shock emission and measure its magnitude would lead to constraints on some important parameters of the GRB ejecta and address the unknown composition of GRBs, baryonic vs. magnetic.

Lead Scientist: Maohai Huang

Allocated time: 23.6 hours

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The Nature of Star-formation in Halos: The HI bridges in the M81/M82 group

We have now reached a relatively mature understanding of the physical processes that regulate the interstellar medium in galaxies, but we are woefully ignorant of the details of the cycles between gas in and outside of galaxies. This is unfortunate because understanding the gas physics in a wide variety of environments is the key to determining the relevance of the physical mechanisms that have been invoked for driving galaxy evolution -- from the feeding of star formation through accretion of cold gas to the regulation of star formation through the mechanical energy ejected by massive stars and AGN. To help to overcome our ignorance about the nature of star-formation in different environments, in this case in a galaxy halo, we propose to use PACS to observe [CII] in many selected regions of the "bridges" of HI in the nearby group of M81, one of the nearest intergalactic gas flows. The M81 group is an excellent target for this type of study because it has a wide range of HI column densities and stars have recently formed in the gas flow between its galaxies. [CII] is the main coolant and an excellent tracer of the cold neutral medium in galaxies. By combining these data with dust maps from Spitzer and Herschel and HI observations, we will investigate the mass balance between the warm and cold neutral medium to constrain the role of turbulence in regulating this balance, which is key to the cooling and fragmentation of gas and to regulating star formation. N-body/SPH simaulations of the interaction will be used to constrain the overall injection of energy in the tidal streams which powers this turbulence and hence the overall phase balance in the gas. Investigating the nature of star-formation in a halo of a galaxy or group is one of the critical first steps in understanding what occurs during the cosmological accretion of gas and thus help determine what processes drive the evolution of the ensemble of galaxies.

Lead Scientist: Matthew Lehnert

Allocated time: 21.6 hours

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Star Formation in X-ray Absorbed QSOs through cosmic time

The nature of the connection between the growth of a black hole via accretion and that of its host galaxy bulge via star formation remains a fundamental question in galaxy evolution. SCUBA/850micron observations of matched samples of high redshift X-ray absorbed and unabsorbed QSOs demonstrated that the X-ray absorbed QSO were far more likely to be detected suggesting that their host galaxies had very high star formation rates. This result implies that the z~2 X-ray absorbed QSO population are undergoing the transition from the main star forming phase and the QSO phase of a massive galaxy. Follow-up X-ray observations of the absorbed X-ray QSOs found that the X-ray absorption is due to an outflowing, ionized wind which is potentially the feedback invoked by theorists to terminate star formation in the host galaxy. However, no QSOs from the samples, X-ray absorbed or unabsorbed, were detected with SCUBA below z=1.5. We propose SPIRE and PACS observations of a sample of 10 X-ray absorbed QSOs in the 1<1.5 redshift range, with the aim of identifying the star-formation properties of their host galaxies as well as their locus within the luminous infrared galaxy population at these redshifts. Our sample is selected such that it will enable us to probe the transition between the star-formation and QSO phases of massive galaxies to lower redshifts than previously and hence allow us to assess the differences (if any) in the relationship between accretion and star formation in massive galaxies as a function of cosmic epoch.

Lead Scientist: Mat Page

Allocated time: 3.1 hours

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Determining the structure of blazar jets with joint SPIRE and PACS observations

The current time-resolved broad-band spectral data for jet-dominated active galaxies cover spectral ranges from radio to gamma-ray bands, with the notable absence of far infrared to sub-millimeter observations. Those observations are absolutely essential in studies of physics and structure of relativistic AGN jets. They will allow to determine the characteristic frequency of synchrotron self-absorption of the radiating material and probe the electron energy distribution in the critical region below the break associated with the synchrotron luminosity peak. Such measurements are required to determine the location and the spatial structure of the dissipation region of the jet. Here, we propose a series of short observations by both SPIRE and PACS of two blazars, PKS 1510-089 and AO 0235+164, repeated every 2 weeks during a 6-week visibility period over two consecutive visibility windows to provide time-resolved history of broad-band spectra in the IR/sub-mm bands. Those observations, together with data in other bands - which will be available via our on-going monitoring programs covering radio, optical, X-ray, and gamma-ray ranges - will provide a unique data set that will greatly advance our understanding of the blazar jets.

Lead Scientist: Marek Sikora

Allocated time: 21 hours

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Herschel Spectroscopic Survey of Warm Molecular Gas in Local Luminous Infrared Galaxies

We propose to survey CO spectral line energy distribution (SLED), from J=4-3 up to J=13-12, on 93 local luminous infrared galaxies (LIRGs; L_{IR} > 1.0E11 L_{sun}) with Herschel SPIRE FTS spectrometer. These galaxies, plus 32 additional LIRGs that will have similar data from existing Herschel programs (mainly the HerCULES project), form a flux-limited subset of the Great Observatories All-Sky LIRGs Survey (GOALS) sample. Our proposal is built on the legacy of GOALS and extends beyond the existing Herschel HerCULES program, which emphasizes more on ULIRGs, to a much needed sample coverage of the more numerous and diverse population of less luminous LIRGs. The data from the proposed observations will not only provide much needed local LIRG templates for future ALMA studies of high-redshift counterparts, but also lend us a powerful diagnostic tool to probe the warm and dense molecular gas that are more closely related to the starburst or AGN activity in the nuclei of LIRGs. The data from this proposal will provide important statistical clues to the interplay between the cold and warm molecular gas, IR luminosity, star formation rate and efficiency, and the diverse properties of LIRGs. Specifically, using the homogeneous CO SLED data from this proposal, together with ground-base, low-order CO line data (mainly J=1-0) and other data that have been compiled for the GOALS sample, we will address the following questions: (1) What is the dominant nuclear power source in individual sample galaxy: starburst or AGN? (2) What are the typical physical properties of warm molecular gas in the nuclei of LIRGs? (3) How do the nuclear warm gas components correlate to the cold gas component, star formation rate and efficiency, dust temperature, etc? and (4) How does molecular gas excitation change along a merger sequence?

Lead Scientist: Nanyao Lu

Allocated time: 83.5 hours

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Characterizing the Dense Molecular Gas in M82 and NGC 1068: Star Formation versus AGN

We propose to use HIFI to observe high-J rotational transitions of HCN, HNC and HCO+ in M82 and NGC 1068. These molecules are excellent tracers of dense molecular star-forming gas. Their high-J transitions (> J = 4-3), which have never been observed before, trace the densest and warmest regions of the molecular clouds, and their detection is only possible with Herschel. M82, a starburst galaxy with no detectable AGN, and NGC 1068, which harbors a luminous AGN, are ideally suited to test models that discriminate between the energy inputs from star-formation versus X-ray radiation from an AGN. The two sources produce significant differences in the gas physics and chemistry in the interstellar medium, and hence can be distinguished by deriving the physical properties of the molecular gas, and looking at diagnostic line ratios. These two galaxies are also important templates for understanding the physical processes in luminous star-forming and supermassive black hole-forming galaxies at high redshifts, which are too faint and highly obscured by dust. In 4.4 hours, we can obtain a total of 22 spectral lines for these molecules for the two galaxies. Combining these high-J observations with low-J measurements from the ground will provide at least 16 lines per galaxy for non-LTE modeling -- an unprecedented number that will put tight constraints on the physical parameters such as gas kinetic temperature, density, column density and mass. The models will also produce line optical depths, excitation temperature, and level populations providing insight into the excitation mechanism. We will use the line ratios of these molecules in the two galaxies to distinguish between excitation from a starburst and AGN by comparing them to the predictions from models in the literature. These two galaxies are also being observed as a part of the VNGS guaranteed time key project with SPIRE-FTS. The CO lines from FTS will probe and characterize the diffuse molecular gas, and will powerfully complement the results of this proposal.

Lead Scientist: Naseem Rangwala

Allocated time: 4.4 hours

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Coeval Black Hole and Host Galaxy Growth in High Redshift Radio Galaxies

High-redshift radio galaxies (HzRGs) are unique markers of the most massive and powerful galaxies in the early Universe, showing signatures of both active galactic nuclei (AGNs) and extreme starbursts. Hence, if the radio-loud AGN phase has a strong effect on the evolution of the host galaxy, it will be most evident in HzRGs. We used Spitzer to carry out a comprehensive survey of 71 HzRGs uniformly covering the redshift range 1<5.2. This survey showed that HzRGs have high stellar masses (M>1e11Msun) out to the earliest epochs probed, and mid-infrared AGN luminosities consistent with the most powerful QSOs. To fully understand the evolutionary state of these HzRGs, we now require accurate star formation rates (SFRs), a measurement which is only possible with Herschel. By combining our Spitzer and ground-based sub-millimeter data with five photometric data bands from PACS and SPIRE, we will separate the AGN and star-forming contributions to the total infrared luminosities. Comparing parameters such as specific SFR against AGN power and radio power, and SFR normalised by accretion rate (from the AGN IR luminosity) against radio jet size, we will test theories of how the radio-loud phase stimulates or suppresses star formation (e.g., 'feedback'). HzRGs also reside in large dark matter over-densities, and are often found in rich (proto-)clusters. The most efficient SPIRE observing mode provides a five arcminute diameter map, which is well matched to our Spitzer data, thereby allowing environmental studies of the HzRGs. Above z=2, Spitzer and SPIRE colours will allow us to select candidate cluster members with redshifts similar to the HzRG. In total, we request 26.8 hours of PACS and SPIRE imaging of the 62 (out of 71) HzRGs which are not in the ROL. These data will enable us to investigate the interplay between AGN and star-formation activity in the early Universe, which in turn will allow us to test predictions of AGN-driven feedback at this crucial epoch. We will also study the HzRG environments.

Lead Scientist: Nicholas Seymour

Allocated time: 26.8 hours

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Understanding the physics of cold gas in the nearby proxies of distant cooling cores

We propose to observe nine nearby Halpha and X-ray bright giant elliptical galaxies to study the physical properties of their coldest gas phases. Recent CO and IR observations reveal that giant elliptical galaxies contain large amounts of cold dust and gas. These systems also often exhibit powerful Halpha emission, but relatively little star formation. These nearby massive galaxies are the lowest redshift proxies of the more distant cluster cooling cores. The first goal of the proposed observations is to understand the physical properties of the coldest gas phases in the nearest, most massive giant elliptical galaxies and to correlate them with the X-ray properties of these systems to understand why this cold gas does not proceed to star-formation. Furthermore, in these galaxies a tight correlation has been found between the their Bondi accretion rate of hot gas and the jet power. An important question, that we seek to answer is: is this correlation so tight because of a steady accretion of hot gas only, or is there another tight correlation between the hot and cold gas phases, leading to an apparent correlation between the Bondi accretion and the jet power? In order to address these question, we will use Herschel to target the atomic cooling lines of [CII] and [OI]. The proposed Herschel PACS observation in combination with existing and upcoming CO, NIR, optical, UV, X-ray, and radio data, will allow us to test our ideas about the mixing of the cold and hot gas phases in the nearest, brightest giant elliptical galaxies and to discriminate between models of heat input into the cold gas by mixing layers and alternative models, such as heating by conduction or shock heating from colliding clouds. In combination with existing and upcoming CO observations, we will be able to determine the mass of the cold gas in the cores of these giant elliptical galaxies. This will enable us to look for a possible relation between the hot and cold gas phases.

Lead Scientist: Norbert Werner

Allocated time: 23.9 hours

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Charting the Cooling Pathways in High-Speed Extragalactic Shocks

Following in the footsteps of ISO, recent observations with Spitzer have revealed a population of galaxy systems which emit a huge amount of luminosity in their pure rotational mid-IR molecular hydrogen lines, in some cases reaching 10-30 percent of the bolometric luminosity. These large line-luminosities are believed to be powered by galactic-scale shocks, which efficiently transfer kinetic energy to smaller dense clouds in the turbulent post-shock medium. However, nothing at all is known about the other important cooling channels for the shocked gas, such as [OI], H2O, OH, and CO, some of which can rival H2 as a coolant. We propose deep PACS and SPIRE spectroscopy of the Giant Shock in Stephan's Quintet and the Taffy Galaxy bridge to quantify the most important cooling channels and determine the physical state of the gas being shocked. The results have implications for understanding the importance of molecular cooling at higher redshift where turbulence and shock-heating may play a role in galaxy formation.

Lead Scientist: Philip Appleton

Allocated time: 37.2 hours

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What inflates the torus? Probing the physical properties of geometrically-thick buried AGN with high J CO lines

The most significant new population of active galactic nuclei (AGN) discovered in recent years is the 'buried AGN' population, uncovered by the Swift satellite. Sensitive X-ray spectroscopy shows characteristics of heavily obscured AGN in these sources, in addition to a very low scattering fraction of low energy photons, which is interpreted as a result of the AGN being buried in dust and gas tori which have an atypically high geometrical thickness. Comprising up to 20 per cent of the entire AGN population, this class constitutes a very important new family of sources, which may be at an interesting evolutionary phase in the AGN life cycle. Yet, very little is known about them, and usual isotropic indicators such as the optical [OIII] forbidden emission line fail to probe their intrinsic powers. The geometrically thick torus picture can result in 1) high gas and dust masses in the tori; 2) increased velocity dispersions and elevated temperatures and pressures; 3) a broad-band spectral energy distribution dominated by cool optically-thick clouds. Far infrared lines provide excellent probes of the physical conditions in the torus, and we intend to use several high J rotational CO lines to test the above picture with Herschel for the first time on several buried AGN for which detailed X-ray spectroscopy exists. These observations will also enable us to search for dynamical signatures of motion in the torus.

Lead Scientist: Poshak Gandhi

Allocated time: 20.6 hours

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Dust in shocks and star-forming regions outside galaxies: PACS and SPIRE photometry of Stephan's Quintet

Stephan's Quintet (SQ) is an extensively studied compact group of galaxies, where tidal interactions have displaced large amounts of gas into the inter-galactic medium (IGM). Spitzer IRS observations revealed an extremely bright H2 line emission from warm molecular gas, coexisting with a giant (40 kpc), X-ray bright shock, attributed to a high-speed (1000 km/s) galaxy collision. The weakness of PAH and mid-IR dust continuum shows that the H2 gas is not associated with star formation (SF) in the shock, in sharp contrast with standard galaxies. Spitzer photometry suggests that most of the SF rather happens outside the center of the shock and galatic disks. Moreover, an extended FIR component, not connected with the galaxies, but coincident with the X-ray halo of the group, may have been revealed by MIPS, but its poor resolution make this identification difficult. This dust may contribute to cool the hot gas, and thus to fuel SF in the halo. In this context of understanding the processes that control SF in the group, we propose to map the thermal dust emission in all the PACS and SPIRE bands. This will allows for the first time to (1) estimate the total cold gas content in the IGM independently from our CO measurements, (2) make use of the Herschel high spatial resolution to separate the dust emission coming from SF regions, the shock, and the X-ray halo, in order to elucidate the origin of the dust emission in the group and its potential role in cooling the intra-cluster gas, and (3) compare the FIR SED in the different regions of the group to dust models in order to constrain the dust size distribution and the structure of the molecular gas. These observations, together with a companion spectroscopy proposal, will provide the missing pieces of the overall energetic bugdet of the main coolants of the galaxy collision. The results will have important consequences on our understanding of the energetics and the role of dust in high-redshift mergers, and in the formation of the first stars and galaxies.

Lead Scientist: Pierre Guillard

Allocated time: 13.3 hours

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Radio Jet Feedback on Molecular and Atomic Gas in Radio Galaxies

We propose Herschel SPIRE and PACS atomic and molecular line spectroscopy and photometry of 23 H2-luminous radio galaxies. Most of these galaxies are IR-weak, such that the kinetic energy output of the radio jet dominates over the radiative output from the AGN accretion disk and star formation in the host galaxy. This new class of galaxies, discovered by Spitzer, has unique MIR spectra with very strong H2 rotational emission lines but weak PAH features compared to normal star-forming galaxies. We may be seeing the direct effects of AGN radio jet feedback, dramatically and fundamentally disturbing the host galaxy interstellar medium in a way that suppresses star formation. Herschel spectroscopy and photometry are essential to inventory the mass and energetics of the atomic and molecular ISM over a wide range of densities and temperatures, and thereby obtain a better understanding of the radio jet feedback mechanism that regulates massive galaxy evolution. We will use shock models to interpret the [O I] and CO emission line spectra and determine the density, temperature, and energetics of shocked molecular gas. Herschel photometry will probe the peak of the IR SED and yield estimates of the total mass of cold dust and cold molecular gas. This will allow us to assess what fraction of the molecular ISM is disturbed by shocks, and understand why and to what extent star formation is suppressed by radio jet feedback.

Lead Scientist: Patrick Ogle

Allocated time: 68.2 hours

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Strong AGN feedback onto the ISM and its effects: A SPIRE FTS view of the molecular gas in 3C293

We propose to use the SPIRE FTS to study the large molecular gas reservoir of the powerful radio galaxy 3C293, the scene of a very strong AGN jet-gas interaction, and the first known case of shock-powered luminous mid-J/high-J CO lines. These were discovered during our large ground-based CO line survey of Luminous Infrared Galaxies (LIRGs) and AGN hosts, and set this object apart as that with the most excited molecular gas of the entire survey, yet with its large gas reservoir (~2x10^9Msol) surprisingly idle in terms of star formation rate (SFR~4Msol/yr). A deep SPIRE FTS spectrum will complete our ground-based CO Spectral Line Energy Distribution (SLED) of this remarkable system and allow excellent constraints to be placed on the thermal state of its molecular gas reservoir and possible suppressing effects of the AGN on star formation in the host galaxy. It will also be the first opportunity to study, locally, powerful AGN mechanical feedback onto the interstellar medium of host galaxies, which will occur frequently in the Early Universe during galaxy formation in the deep gravitational wells of proto-clusters marked by such powerful radio galaxies.

Lead Scientist: Panteli Papadopoulos

Allocated time: 6.1 hours

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Herschel spectra of low-z QSOs: measuring radiative feedback, radiation pressure and star formation

Observations with the SPIRE FTS of the ULIRG-QSO Mrk231 have shown that the CO rotational ladder can be used to separate the contribution of Photon-Dominated Regions (PDRs), powered by star formation, from that of X-ray-Dominated Regions (XDRs), powered by the AGN. We propose to apply this diagnostic to a sample of 5 low-z QSOs with detections in CO, in order to: (1) derive size, density, column density and X-ray illumination of the circumnuclear medium; (2) measure radiative feedback and derive radiation pressure by the AGN on the surrounding medium, in order to probe its ability to drive the recently discovered molecular outflows and disperse the nuclear gas, and to assess its importance for the dynamical support of the circumnuclear medium, which will affect dynamical black hole mass measurements; (3) determine the importance of star formation in the host galaxy for the observed infrared luminosity. Our observations consist of SPIRE-FTS spectra of 5 QSOs, and PACS spectra to measure the higher CO lines in the brightest object only. These observations will address the evolutionary relation between QSOs and ULIRGs and the role of QSOs as drivers for the transition between actively star forming and passive galaxies. They will also constitute a low-z benchmark for future CO observations of high-z QSOs with ALMA, which can only be provided by Herschel, and which is not covered in the current Herschel programme.

Lead Scientist: Paul van der Werf

Allocated time: 28.1 hours

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Gas excitation through black hole accretion and star formation in the centers of active galaxies.

Stunning observations with SPIRE FTS of Mrk 231 have shown that CO lines are very bright up to J=13-12, and there is no sign of a decline in the CO Spectral Line Energy Distribution (SLED). Our SPIRE FTS spectra show that this is a common feature of AGN type galaxies. Therefore, we propose to observe a set of 4 very high-J CO line transitions using the PACS spectrometer, for 5 of these well studied proto-typical (Ultra-)Luminous Infrared Galaxies ((U)LIRGs) and one starburst galaxy. The question of the relative role and contribution of AGN to the far-infrared luminosities of local (U)LIRG systems has long been a problem in our understanding of the evolutionary path of these objects, and as well for the interpretation of deep far-infrared surveys. Our SPIRE FTS and our ground-based CO line observations together with the PACS observations in this program will allow us, for the first time, to complete a full CO SLED for a set of (U)LIRGs. Combining this with our models of Photon Dominated Regions (PDRs) and X-ray Dominated Regions (XDRs), we will then be able to determine the physical state of the interstellar medium and estimate the starburst/AGN contribution to the total energetics of these systems.

Lead Scientist: Rowin Meijerink

Allocated time: 22.4 hours

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Determining the Bolometric Luminosity of AGN

Determining the bolometric luminosities of AGN is key to understanding their evolution. Uncertainties in the total radiation from AGN translate into uncertainties in their lifetimes, Eddington ratios, mass accretion rates, the form of their radiation, and the predicted black hole spin. However, we still have major problems in measuring this critical quantity. AGN and their host galaxies emit a large fraction of their light in the MIR to FIR, but the origin of this radiation and the connection to the AGN are not well understood. It is not clear whether this radiation is associated with the AGN or with star formation in the galaxy. We propose to use Herschel's unique capabilities to establish the properties of the Swift-BAT all sky sample of local AGN selected at 15-195 keV. We will measure the MIR to FIR (65-500 microns) properties of a complete low-redshift sample (309 objects at z<0.05). The Swift-BAT survey is the least biased all sky survey for AGN with respect to host galaxy properties and obscuration in the line-of-sight, and thus it is superior to optical, IR, or radio surveys for understanding the the nuclear component of the MIR to FIR radiation from active galaxies. The low redshift of our sample, the uniformity of selection, and the large amount of parallel data which have already been obtained (Spitzer, optical, and X-ray spectra, and optical and UV imaging) will allow the most precise determination of the physical origin (AGN versus star formation) of the light. The low redshifts allow the best possible angular resolution for spatially separating star-formation and nuclear components, while only requiring short Herschel exposures. The Herschel BAT survey will provide a comprehensive database for determining the bolometric light of AGN and will be an invaluable reference sample for analyzing higher redshift AGN. It will be a powerful resource for many years to come. We will make it available in a comprehensive and accessible form as rapidly as possible.

Lead Scientist: Richard Mushotzky

Allocated time: 59 hours

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Comparing the Dust Emission from High Redshift Lyman Break Galaxies with their Best Low Redshift Analogs discovered by GALEX

We propose to use PACS to characterize the dust emission in UV-selected starburst galaxies at z<0.3 from our on-going survey of "Local Lyman Break Analogs" (LBAs). This survey was specifically designed to find and study rare, nearby galaxies from the GALEX all-sky survey that are most similar to the population of Lyman Break Galaxies (LBGs) at z>2-3. The LBAs are similar to LBGs in terms of mass, SFR, age, metallicity, attenuation, size, morphology, kinematics, and ISM. Because of these remarkable similarities, we can perform a much more straightforward comparison of their properties. Specifically, we will use PACS to sample the far-IR dust emission from 28 LBAs, and study its relation to other physical properties of these starbursts to a level of accuracy that can not be achieved for similar UV-selected starbursts at high redshift. We will address the following questions: (1) What are the contributions from hot/cold dust emission to the total (UV+IR) energy budget, and how do these compare with LBGs? (2) How do LBAs relate to their IR-luminous counterparts in the local Universe? (3) Do LBAs follow the locally calibrated "beta-IRX relation" that is commonly used to calculate dust-corrected SFRs at high redshift? (4) Can we understand offsets from the beta-IRX relation in terms of other properties (e.g., complex star formation histories or modified extinction laws)? (5) What are the star formation efficiencies in LBAs as a function of their triggering mechanism, and are these similar to those inferred for LBGs? Combined with our existing broad based, multi-wavelength observations from GALEX, SDSS, HST, Spitzer, VLT, Keck, XMM, and the VLA these data will provide crucial information on the interplay of stars, gas and dust in the LBG analogs. This will aid us in our understanding of their UV-luminous counterparts at high redshift, just as our understanding of local ULIRGs has been fundamental for the study of the most IR-luminous sources at high redshift.

Lead Scientist: Roderik Overzier

Allocated time: 28.6 hours

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Testing the XDR/High-J CO Paradigm in Nearby Galaxies

One of the most exciting first results from SPIRE and PACS spectroscopy is the detection of high-J CO emission in galaxies. Such emission has long been proposed as a tracer of X-ray dominated regions (XDRs) produced by AGN, and as a powerful diagnostic tool for future millimeter-wave study of AGN at high redshift. The shortest wavelength submillimeter CO lines detected by SPIRE-FTS in the X-ray luminous ULIRG Mrk 231 are interpreted as arising from an extended XDR, providing strong observational support for the XDR/high-J CO connection. However, our group (SHINING; PI E. Sturm) has used PACS to detect even higher-J far-IR CO emission in a few nearby galaxies, including 2 starburst galaxies with little evidence of a luminous AGN. Can high-J CO emission also be produced in gas heated by the UV radiation or mechanical output of a starburst? To address this question we propose to measure a set of far-IR CO lines in 4 nearby AGN and 4 starburst galaxies, as well as in 2 merging systems with large masses of shock-heated molecular gas. Does the high-J CO line SED reflect the different excitation mechanisms in these template objects? We additionally propose to use OH line observations to estimate the abundance of this molecule, which is a sensitive tracer of X-ray-driven chemistry. The OH line profiles will also be used to search for evidence of molecular outflows, which may drive shock heating. Each of these galaxies will have SHINING GT observations of the set of far-IR fine-structure lines, which includes important tracers of UV-, X-ray-, and shock-heated gas. The AGN subsample is restricted to the most nearby systems, where the high spatial resolution of PACS is sufficient to separate the nuclear AGN-heated gas from the circumnuclear star-forming regions. The PACS CO data obtained here will provide the first well-sampled far-IR extragalactic CO line SEDs, and will be an essential reference for future high redshift studies.

Lead Scientist: Steven Hailey-Dunsheath

Allocated time: 32.2 hours

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The physical conditions of star formation at low metallicity: the Magellanic clouds as corner stones

How galaxies convert their gas reservoirs into stars is a stumbling block in understanding galaxy evolution. The far IR and submm cooling lines arising from photodissociation regions (PDRs) are the key diagnostics of the interplay between star formation and the evolving ISM throughout the course of the history of the universe. While effort has been put into physics of PDRs and star formation in the Galaxy and other metal-rich galaxies, little attention has been put into understanding the effects of the lower metal abundance on the these processes. Here we propose PACS ([CII] 158 um, [OI] 63 um, [OI] 145 um, [OIII] 88 um, [NII] 122 um) and SPIRE FTS spectroscopy towards carefully selected star forming sites in the nearest low metallicity galaxies, the Magellanic Clouds (MCs) as a benchmark study to calibrate the primary diagnostics of low metallicity environments which are crucial for ALMA high redshift science. The proximity of the MCs allows Herschel to resolve molecular clouds at 3 pc scale. Our targeted regions span a wide diversity of environments, including dense molecular gas and ionised regions. These new data, together with existing IRS spectra, Herschel and Spitzer photometry, and a wealth of ground−based data including the MAGMA CO data, will allow us to address important unresolved issues: 1) the amount of molecular gas hidden in a low extinction phase where CO is photodissociated and thus not detected; 2) the dependence of the FIR fine structure lines, CO excitation and gas thermodynamics on environment; and 3) the structure of PDRs at low metallicity. Our results will be key to interpreting FIR fine structure lines and CO observations of more distant systems. We will produce PDR models tested at low metallicity, a library of CO excitation at low metallicity, and a calibration of the amount of "CO−free" molecular gas as a function of environment. In addition, multi−line maps covering the main coolants of the atomic and molecular gas, represent a data product with lasting legacy value.

Lead Scientist: Sacha Hony

Allocated time: 79 hours

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Exploring the Dust Content of Galactic Winds with Herschel

We propose a PACS imaging survey to study galactic winds from nearby starburst galaxies. We will obtain very deep PACS 70/160 micron data to map the detailed distribution of cold (T<100 K) dust in a small but representative sample of galaxies that are known to host outflows. These data will be compared to state-of-the-art, 3D numerical simulations of superwinds and predicted PACS fluxes. Direct and indirect evidence shows that dust is present on large (kiloparsec) scales in outflows in some starburst galaxies. However, this dust has never been mapped at wavelengths of 70-160 microns, and its geometry, mass, and energy are almost completely unknown. Recent spectacular SPIRE results on M82, as well as our own Spitzer IRAC 8-micron and MIPS 24-micron maps of the targeted wind galaxies, suggest that this survey will yield exciting new insights on the cold dust in these outflows. We will ascertain the significance of dusty superwinds in the context of outflow physics and the impact of the outflows on the host galaxies and the intergalactic medium. We will compare the distribution, mass, and energy of the cold dust to optical emission-line and absorption-line, mid-infrared, X-ray, and radio data compiled by us and other groups. We note that several of our targets are being mapped with PACS and SPIRE as part of key programs (KPs). However, the objectives of these programs are heterogeneous and often neglect the importance of outflow science. This is reflected in the depth of the observations at the critical shorter wavelengths, near the peak of the IR SED: the PACS KP data will not be able to detect the FIR emission expected from a M82-like wind in our galaxies. There is currently no plan to address this problem but one is necessary to take full advantage of Herschel in this field. The proposed PACS survey will go nearly an order of magnitude deeper than the KP data and will complement the SPIRE portion of the KPs, while providing many advantages over the SPIRE data.

Lead Scientist: Sylvain Veilleux

Allocated time: 48.7 hours

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Molecular Outflows in Gas-Rich Mergers

The role of galactic winds in gas-rich mergers is of crucial importance to understand galaxy and supermassive black hole evolution. In recent months, our group has had two major scientific breakthroughs in this area: (1) the discovery from our SHINING guaranteed-time PACS survey of ultraluminous infrared galaxies (ULIRGs) of a 1400-km/s molecular OH wind in the nearest quasar, Mrk 231. (2) The independent discovery from mm-wave CO interferometric observations in the same object of a spatially resolved molecular wind with estimated mass outflow rate 4-10x larger than the star formation rate. Remarkably this CO outflow coincides spatially with blueshifted neutral gas in our optical spectra. This powerful outflow may be the long-sought "smoking gun" of quasar mechanical feedback purported to transform gas-rich mergers. However, our SHINING survey contains only 2 other warm quasar-dominated late stage mergers like Mrk 231 (one of them also shows a high-velocity OH outflow, while the other has not yet been observed). So here we request 32.5h to obtain high-S/N OH 119 um spectra of 15 additional quasar-dominated late stage mergers. We have a comprehensive set of multiwavelength data on all of these objects, including crucial spatially resolved optical Na ID absorption spectroscopy. The combined sample of 20 cold ULIRGs and 18 warm ULIRGs/QSOs will allow us to address the role of mechanical feedback in mergers after the first peri-passage, i.e. when mechanical feedback from the starburst/QSO is predicted to be at its maximum. We will look for trends between the basic measured properties of OH (incidence of absorption, kinematics, column densities) and host/evolutionary indicators. In cases of kinematic match between OH features and spatially resolved neutral-gas clouds, we will be able to infer the masses and kinetic energies of these outflows. Measured velocities in excess of ~1000 km/s or inferred mass outflow rates much larger than the star formation rates would be telltale signs of AGN-driven winds.

Lead Scientist: Sylvain Veilleux

Allocated time: 32.5 hours

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Hydrogen Fluoride Absorption Toward Luminous Infrared Galaxies

We propose to carry out a HIFI survey of the fundamental transition of HF at 1.232 THz toward 24 relatively nearby IR-bright galaxies to probe their ISM physical conditions. HF is a very new tracer of the diffuse and dense ISM, with its use originating with the ISO detection of the J=2-1 transition in absorption toward Sgr B2. Widespread HF J=1-0 absorption toward galactic starforming regions has been recently detected by HIFI and HF emission in an extragalactic nucleus has been detected at low spectral resolution by SPIRE. We intend to make use of this unique probe by conducting a high spectral resolution (10-20 km/s) HIFI absorption survey toward continuum-bright external galactic nuclei exhibiting a wide range of physical properties (AGN, starbursts, mergers). HF is chemically very strongly bound and therefore resistant to photodissociation. Our study is facilitated by this resistance of HF molecules to destruction, which will occur in the extreme environments in the galactic nuclei. HF will thus be a very useful probe in regions of the ISM where more traditional gas probes, such as CO, are more prone to error (e.g., the use of the X-factor). With the simplifying assumption that all fluorine is likely to be locked up in HF, and that the HF molecules will reside in the ground rotational state, we can measure the hydrogen column density and mass of the nearby IR-bright galaxies. Observations of the local galaxies proposed here are the first step toward using HF as a tracer of the gas in high-redshift galaxies. By looking at extragalactic continuum-bright nuclei, we will also be able, through the use of the HIFI Wide Band Spectrometer, to simultaneously search for absorption through the Milky Way halo cloud population. Here, the rapid formation rate of HF and its strong molecular bond will allow us to detect HF absorption toward the tenuous and quiescent mostly HI clouds making up the galactic halo. These diffuse, cold regions may not otherwise be detectable in CO emission or other commonly uses tracers.

Lead Scientist: Thomas Phillips

Allocated time: 40.5 hours

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Monitoring of the far-IR SED of two archetypical quasars

We propose quasi-simultaneous multiband photometry with Herschel and other ground- (VLBA, Effelsberg, SMA, OAGH, NOT) and space-based (Swift, Fermi) facilities to obtain an unprecedented coverage of spectral energy distribution (SED) of two archetypical radio-loud quasars 3C273 and 3C279 and follow evolution of the SED on monthly timescale. The wide wavelength coverage of the Herschel instruments PACS and SPIRE will allow us to sample the region of the synchrotron peak of the SED in these sources and monitor its variability, which provides a way to distinct between various emission components expected in this region (one or more synchrotron components, thermal emission from dust). The combination of the Herschel data with the other facilities will provide almost completely sampled SEDs that will put strong constraints on the blazar emission models.

Lead Scientist: Tuomas Savolainen

Allocated time: 6.8 hours

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Unveiling the dark side of the Gamma-Ray Bursts with Herschel Far Infrared Photometry

Dark gamma-ray bursts (GRBs) are bursts with a detected X-ray afterglow but not detected optical afterglow in spite of deep follow-up observations. Approximately 40% of all bursts belong to this category. Possible explanations for the lack of an optical detection are a high redshift (z>7), which however can not account for the whole dark population, and extinction due to the host galaxy dust. We plan to take advantage of the Herschel capabilities to spot for the first time these objects in the far infrared band, using PACS. The requested observations will shed light on the nature of dark GRBs, allowing us to put constraints on the dust content, on the afterglow physics and to search for the host galaxies of these elusive sources.

Lead Scientist: Valerio D'elia

Allocated time: 28.1 hours

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Molecules in the Distant Universe: Herschel Spectroscopy of Damped Lyman-alpha Quasar Absorbers

Observations of interstellar molecules in distant galaxies are essential for investigating the chemical evolution of galaxies. Absorption line systems in quasar spectra, especially the damped Lyman alpha (DLA) absorbers, provide excellent venues for directly studying the interstellar matter (ISM) in distant galaxies, selected independently of the galaxy luminosities. A few cold, dusty absorption systems have been discovered using radio surveys and the Sloan Digital Sky Survey. These absorbers, far richer in dust/molecules than the general DLA population, give us rare opportunities to probe molecular clouds at high redshift. Here we propose Herschel observations of 4 quasars with such DLAs at z < 1.5 to further observe their molecular content. These DLAs exhibit H I 21-cm absorption and other signatures of cold ISM such as the 2175 A bump from carbonaceous dust or low spin temperature. Furthermore, we have detected 9.7 micron silicate absorption toward two of these DLAs with Spitzer IRS. We request HIFI spectroscopy to observe absorption lines of CO, CN, NH, H2O, and SPIRE photometry of the 4 quasars to determine the continuum accurately. In addition, we request SPIRE photometry of 10 other quasars with strong absorbers rich in dust/metals, in order to identify bright targets for future Herschel spectroscopy. Our overall science goals are: (1) to estimate molecular abundances and kinematics of the absorbing gas; (2) to constrain isotopic ratios such as 12C/13C from 12CO/13CO or 12CN/13CN; (3) to estimate the cosmic microwave background temperature at the absorber redshifts. Finally, (4) the proposed program will help to further constrain the cosmic variation of fundamental constants such as the electron-to-proton mass ratio.

Lead Scientist: Varsha Kulkarni

Allocated time: 36.8 hours

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Major-merger, starburst.... what next?

A popular scenario to explain the increase in number of quiescent, elliptical galaxies over cosmic time is one in which gas-rich major mergers lead to strong starbursts which exhaust fuel supplies and transform the morphology of galaxies from disks to spheroids. In this proposal we describe how PACS+SPIRE photometry can directly test this scenario. We present a unique sample of massive starburst-to-post-starburst galaxies in the local Universe (z<0.05), which have undergone a starburst between 10Myr and 1Gyr ago. The sample is drawn from a statistically complete sample of Sloan Digital Sky Survey (post-)starburst galaxies, i.e. they have experienced the same strength starburst. Together with CO molecular gas masses (already obtained), we will use the Herschel photometry to track the evolution of dust mass, dust temperature and dust-to-gas ratios for 1Gyr following the starburst. This will allow us to directly test (1) how star formation is quenched following a starburst: gas exhaustion, expulsion or change of gas state; (2) whether massive starburst galaxies are the progenitors of red-sequence galaxies. Additionally, we will use our accurate starburst ages to test whether supernovae or post-AGB stars contribute significantly to the enrichment of the interstellar medium (ISM) with dust. By combining with results from similar studies of local merger- or IR-selected galaxy samples we will calculate a "duty-cycle" for IR bright galaxies, crucial for understanding the selection of high-z galaxy samples. By combining our (post-)starburst galaxy sample defined upon the physical properties of starburst age and strength, with the diagnostic capabilities of CO and dust emission for probing the physical state of the ISM, this dataset will provide the best observational constraints to date on the merger+starburst evolutionary pathway from star-forming spiral to quiescent elliptical galaxy.

Lead Scientist: Vivienne Wild

Allocated time: 4.7 hours

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Keeping the cool gas in galaxy clusters warm.

We propose SPIRE FTS spectra to determine the source of heating of the cool/warm (100-300 K) gas in the Brightest Cluster Galaxy NGC-1275, the brightest of all cluster cool-core galaxies. The heating mechanism in BCGs is unknown and crucial to understanding analogous "negative feedback" processes in star-forming galaxies at high redshift. Our current mm-CO, PACS, nearIR and optical data on this cluster indicate that the SPIRE measurements will detect many CO lines and possibly H2O+ and OH+ lines that will determine the temperature, and density of the most important component of this warm gas. The ratios of the CO lines, and the presence or absence of the ionized lines, and the dependence of these lines with distance from the central AGN should allow us to choose between the several possible heating and excitation mechanisms: soft X-rays, cosmic ray ionization, and C- and J- shocks from AGN induced turbulence.

Lead Scientist: Walter Jaffe

Allocated time: 24.9 hours

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Open Time (Round 2)


Far-infrared imaging of nearby Seyfert galaxies: Exploring the dust heating mechanisms in the nuclear regions and host galaxies

We propose to obtain PACS and SPIRE imaging observations of a sample of nearby (d<60Mpc) Seyfert galaxies. The main goal of this proposal is to understand the processes heating the dust in nearby Seyfert galaxies, including dust heated by the AGN, by on-going star formation activity, and by the general ISM radiation field. The galaxies are part of our own survey of local AGN to be observed with the mid-infrared CanariCam instrument on the 10.4-m Gran Telescopio Canarias. The sample contains 31 Seyferts of different types (1, 1.5, 1.8, 1.9, 2) and covers a large range in AGN luminosities. In this proposal we only apply for observing time for those galaxies not observed previously with PACS and SPIRE. The unprecedented angular resolution and sensitivity of the proposed PACS and SPIRE imaging observations will be used to: (1) map and quantify the on-going star formation activity across the host galaxies of local AGN, (2) obtain spatially-resolved and integrated accurate estimates of the dust temperature and content of the host galaxies, and (3) put tighter constraints on the properties of the clumpy torus by fitting their nuclear IR spectral energy distributions.

Lead Scientist: Almudena Alonso-Herrero

Allocated time: 5.6 hours

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Herschel photometry of the nearest radio-quiet quasar

PDS456 is a southern ultraluminous IRAS galaxy at redshift z=0.18. It hosts one of the nearest powerful optically-visible AGN, and is one of the most extreme known QSOs. It is hidden behind a significant amount of optical extinction, and so its host galaxy is relatively difficult to investigate. It is know to have a very luminous, hot dust SED, and yet is not detected at submm wavelengths. We propose a Herschel PACS and SPIRE photometry observation to determine exactly the broad-band shape of its spectral energy distribution (SED), and to provide a precise determination of its bolometric luminosity. The shape of the SED will provide help in interpreting the role of the AGN and possible star-formation activity in powering this object. Without Herschel, the peak of the SED of this unique source will not be known accurately, even as an excellent understanding of its morphology, gas dynamics and astrophysical processes is built up using ground-based adaptive optics imaging, ALMA and JWST.

Lead Scientist: Andrew Blain

Allocated time: 1.3 hours

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The Mass and Structure of Molecular Gas in the Small Magellanic Cloud and the Herschel Legacy at Low Metallicity

We propose a spectroscopic survey of the Small Magellanic Cloud (SMC) designed to measure the impact of metallicity on the interstellar medium and specifically to determine the mass and structure of molecular gas residing in a "CO-dark" phase. The SMC is the nearest truly low-metallicity, actively star-forming galaxy and shows the best evidence of any galaxy of being dominated by "CO-dark" H2 gas. This makes the SMC an absolutely unique target and the best source to study how the H2 reservoir, the relation between star formation and H2, and the relation between H2 and CO are affected by metallicity. These are key problems with far-reaching implications for the evolution of the star formation across cosmic time and the interpretation of high-redshift observations in the ALMA era. Our survey consists spectral mapping with FTS+PACS ([CII], [OI], [NII], [OIII]) of 5 regions selected to span a wide range in relevant parameter space and enable a clean and precise measurement of the abundance of "CO-dark" molecular gas. This rich dataset will have lasting legacy value and address a key gap in the Herschel legacy, enabling studies in a wide range of other topics. Moreover, the coIs will publicly distribute the data products 18 months after the end of observations. The team have extensive leading expertise on these science topics, as well as modeling and data reduction.

 

Lead Scientist: Alberto Bolatto

Allocated time: 46.4 hours

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Dust properties and resolved star formation relations in CO-rich Atlas3D early-type galaxies

We propose to obtain PACS and SPIRE photometry of 39 early-type galaxies (ETGs) with molecular gas maps from the Atlas3D survey. These data will allow the spatially-resolved relations between molecular gas and star formation (i.e. the star formation law) and radio continuum and FIR emission to be studied in a large sample of ETGs for the first time. We will determine whether ETGs follow the same relations as found in late-type galaxies and if not, consider what galaxy properties correlate most with their deviations (stellar mass, environment, bulge-to-disk ratio). The Atlas3D survey is the perfect survey to do this for, with a wealth of data and analysis available for all sample galaxies, including CO, HI and radio continuum interferometry which are critical to this work. Another aim of this proposal is to constrain the proportion of dust heated by old stellar populations in ETGs. Even in star-forming ETGs, the specific star formation rates are low, making this an even bigger concern than for spirals. Thirdly, these observations will constrain the origin of dust and gas in ETGs via the dust-to-gas ratio (low ratios imply gas accretion from an unenriched source). Our previous results suggest a strong dependence of gas accretion history on environment, with external accretion being important in the field only. In this case, we expect all cluster galaxies to have high dust-to-gas ratios, but a more varied assortment in the field galaxies. The Herschel data will allow us to test this hypothesis.

Lead Scientist: Alison Crocker

Allocated time: 27 hours

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High-J CO Emission Lines in Molecular Gas-Rich Radio Galaxies with Low and High Star Formation Efficiencies

We propose Herschel observations of the CO Spectral Line Energy Distribution (SLED) in a sample of seven local (z < 0.1) radio galaxies with the highest CO(1-0) luminosities. These radio galaxies fall into two classes in terms of their infrared (IR)-to-CO luminosity ratio, or ``star formation efficiency'' - those with high IR/CO similar to IR luminous starburst galaxies, and those with low IR/CO ratios comparable to low luminosity spiral galaxies. The observed dichotomy in IR/CO likely represents (1) intrinsic differences in the star formation efficiencies within the sample, (2) an enhancement in the infrared luminosity of the galaxies with high IR/CO by AGN dust heating, (3) or inaccuracies in the star formation efficiency determinations introduced through the use of a constant CO luminosity-to-molecular gas mass conversion factor, or through the use of CO(1-0) to trace the molecular gas actively involved in star formation. With the Herschel Spire FTS, we will detect high-J (>5) rotation CO transitions, enabling (1) an accurate determination of the star-forming molecular gas mass, temperature and density, and thus a more accurate estimate of the star formation efficiency, (2) an assessment of the effect AGN and starbursts have on the excitation of the high-J CO transitions, and possibly of H2O and OH lines. In addition, we will make use of our data in concert with the HERCULES dataset to (3) determine whether the high-J CO transitions scale with far-IR luminosity, and are therefore useful tracers of the star formation rates of radio galaxies. These observations will provide, for the first time, a truly robust insight into star formation and AGN heating of gas in radio−selected, AGN−dominated environments. In addition, the analysis will be applicable to the interpretation of high−J CO emission from high redshift AGN hosts done with Herschel and ALMA.

Lead Scientist: Aaron Evans

Allocated time: 20 hours

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Imaging a Complete Sample of Equatorial Star-Forming

We propose imaging with PACS (70+160 mciron) and SPIRE to ensure full resolved far-infrared (FIR) spectral energy distribution (SED) coverage of a complete equatorial sample of star-forming galaxies. This sample consists of every equatorial, face-on, star-forming galaxy of large angular extent and luminosity larger than M33. Because of their accessibility to all major facilities, particularly ALMA and the EVLA, these are the natural targets of the next generation of local galaxy studies. Herschel data are critical to estimate star formation rates, dust masses, and energetics in these galaxies and no comparable coverage of the IR SED will be possible in the foreseeable future. Without our proposed program only 13 of the 67 galaxies in this key sample will have high resolution data that span the IR peak, hindering studies of the life cycle of dust, dependence of star formation on host galaxy and local conditions, and development of robust calibrations of star formation rate tracers and the CO-to-H2 conversion factor. Observations of this sample therefore would represent a key part of Herschel's legacy and significantly enhance the nearby galaxy science from the next generations of northern and southern telescopes. In order to ensure maximal yield from both Herschel and ALMA/EVLA, we commit to waive our proprietary period and rapidly release our reduced data products.

Lead Scientist: Adam Leroy

Allocated time: 55.7 hours

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The [CII]/CO ratio as a tool to measure the molecular

We request 78 hours of observing time to obtain 5-10 sigma detections of the [CII]158um line for a complete sample of 103 star-forming galaxies with 9.0<log(M*/Msun)<10.2 . These observations form the bedrock of an ambitious new program to understand the gas accretion and star formation histories of low mass galaxies in the local Universe. In this stellar mass range, galaxies are dominated by cold gas rather than stars, gas-phase metallicities drop below solar, and CO line luminosities quickly become a poor proxy for the total molecular gas content of a galaxy. We note that the majority of star-forming galaxies in the high redshift Universe (z>2-3) likely lie in this regime, irrespective of their mass. By measuring [CII] line fluxes with Herschel/PACS, our hope is to disentangle variations in CO line flux measurements that might arise because galaxies have different gas accretion histories, from systematics in the CO-based molecular gas measurements resulting from changes in the structure and chemical compositions of the molecular clouds themselves. The majority of galaxies in our sample already have HI data from Arecibo. Total star formation rates and stellar masses have been estimated using multi-band GALEX and SDSS photometry. We are simultaneously applying for IRAM 30m telescope time to obtain CO line fluxes, and MMT time to obtain long-slit spectroscopy to estimate gas-phase metallicity and dust extinction profiles for the galaxies in our sample. At the very least, by tracking the [CII]/CO ratio as function of stellar mass, SFR and metallicity, we will empirically (and hence robustly) determine the global properties of galaxies for which the standard XCO factor no longer provides accurate total molecular gas masses. This will be crucial input to future studies of CO in high-z galaxies.

Lead Scientist: Amelie Saintonge

Allocated time: 77.7 hours

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Accurate SFRs and dust masses across the star-forming main sequence of galaxies: PACS observations of a local unbiased sample.

Recent studies in galaxy evolution have uncovered a tight "main sequence" (MS) of star-forming galaxies that evolves with redshift. We propose to obtain Herschel FIR photometry for 100 galaxies from the S5 galaxy sample (Spitzer SDSS Statistical Spectroscopic Survey)---the largest optically selected sample of galaxies with Spitzer mid-IR spectroscopy---in order to test and improve our understanding of this MS. We will derive accurate IR luminosities, dust temperatures, dust masses and derived star formation rates for a representative sample of normal star-forming galaxies extending up to 2 sigma above and below the MS at z~0.07. In combination with the extensive multi-wavelength data that exists for the S5 sample, PACS/Herschel photometry will provide the critical, final piece of the puzzle that we need to track the evolution of physical parameters across the main sequence. Furthermore, we anticipate that this survey will produce a unique data set that will connect Herschel studies of local and distant galaxies to the vast archival resource of SDSS and corollary observations.

Lead Scientist: Benjamin Bertincourt

Allocated time: 19 hours

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New HErschel Multi-wavelength Extragalactic Survey of Edge-on Spirals (NHEMESES)

Edge-on spiral galaxies are a unique perspective on the vertical structure of spiral disks, both stars and the iconic dark dustlanes. The thickness of these dustlanes can now be resolved for the first time with Herschel in far-infrared and sub-mm emission.

Resolved far-infrared and sub-mm observations of edge-on spirals will impact on several current topics. First and foremost, these Herschel observations will settle whether or not there is a phase change in the vertical structure of the ISM with disk mass. Previously, a dramatic change in dustlane morphology was observed as in massive disks the dust collapses into a thin lane. If this is the case, the vertical balance between turbulence and gravity dictates the ISM structure and consequently star-formation and related phenomena (spiral arms, bars etc.). We specificaly target lower mass nearby edge-ons to complement existing Herschel observations of high-mass edge-on spirals. Secondly, the combined data-set, together with existing Spitzer observations, will drive the generation of spiral disk Spectral Energy Distribution models. These model how dust reprocesses starlight to thermal emission but the dust geometry remains the critical unknown. And thirdly, the observations will provide an accurate and unbiased census of the cold dusty structures occasionally seen extending out of the plane of the disk, when backlit by the stellar disk.

We ask for priority one for the remaining 8.9 hours of PACS and SPIRE observations of low- and intermediate-mass disks complement slated Herschel observations of massive edge-on spirals and existing Spitzer observations in the near-infrared.

Lead Scientist: Benne Holwerda

Allocated time: 8.9 hours

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Spirals Bridges and Tails: The Herschel View of Dust in Interacting Galaxies

The tidal features produced by gravitational interactions between galaxies may contribute significantly to the enrichment of the intergalactic medium in dust and heavy elements. However, at the present time little is known about the dust content and properties of tidal structures. To address this lack, we propose to use the PACS and SPIRE instruments on Herschel to image a sample of nine nearby interacting galaxies in six far-infrared/submm broadband filters. We will map the dust column density and temperature in the main bodies and tidal features of these galaxies, and compare the far-infrared/submm properties of these features with those of normal spirals and dwarf galaxies. We will compare the Herschel maps with already acquired GALEX UV, Spitzer IR, and ground-based optical data, and with population synthesis and radiative transfer codes, to investigate dust heating mechanisms and extinction in these galaxies. We will compare with available radio maps to investigate dust/gas ratios and star formation triggering mechanisms, and compare with numerical simulations of the interactions. Our sample includes the closest and best-studied examples of tidal dwarf galaxies and accretion-driven star formation. These will provide a good testbed for interpreting high redshift systems.

Lead Scientist: Beverly Smith

Allocated time: 25.9 hours

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Physical conditions in disky U/LIRGs from far-IR line flux ratios - low-z analogs for high-z starforming galaxies

We propose for PACS spectroscopy of the [O III] 88 micron and [N II] 122 micron lines, and SPIRE far-IR photometry, to observe a sample of 16 low-redshift IR-luminous galaxies, at log L_IR = 11.6 to 12.2 Lsolar, that are distinguished by large size and non-merger structure. In OT1 we are obtaining PACS spectra of [C II] 158 and [O I] 63 microns for this sample. These galaxies are interesting because they have high SFR activity spread over a large physical area, rather than concentrated into extremely dense nuclear regions, as in most local major merger ULIRGs. They are good analogs for high-redshift IR-luminous galaxies, which have far-IR spectral shapes different from local ULIRGs. At z>1, much of the star formation in massive galaxies is at LIRG and ULIRG levels, and U/LIRGs dominate the IR luminosity density. Understanding star forming regions in high-z IR-luminous galaxies is necessary to understand the conditions in which most of the stars in massive galaxies formed. In a few high-z lensed ULIRGs where [C II] can be observed, [C II]/FIR is high, like local star-forming galaxies and unlike local ULIRGs. [C II] is a major cooling line in PDRs and the far-IR lines probe the physical conditions and UV intensity in IR-emitting regions. In our sample observed so far in OT1, [C II]/FIR is high - they do not suffer the "[C II] deficit" found in local ULIRGs. This suggests that redshift evolution in IR SEDs and line ratios are related to the larger extent of star formation, and that this low-z disky sample are good analogs. The [O III] and [N II] lines provide more detailed probes of the ionization state, gas density, and ionizing SEDs in the star-forming regions: in published samples the [O III]/FIR ratio shows tension with simple models for the line deficit, and [N II] and [O III] can constrain ionizing SED versus gas density. The SPIRE far-IR photometry will constrain the total IR luminosity and cold dust in these galaxies, which have cool IR colors and far-IR fluxes rising past 100 microns.

Lead Scientist: Benjamin Weiner

Allocated time: 20.4 hours

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The Submillimeter Continuum in the Magellanic Clouds

Herschel observations have revealed an excess (over the expectations of naive models of dust emission) of long-wavelength emission in many regions of the Magellanic Clouds. We propose to determine the nature of this excess by measuring select regions at higher spectral resolution using the SPIRE FTS. Our measurements will demonstrate whether emissivity changes, spinning dust, cold dust, or line emission are the cause of the excess emission observed at long wavelengths.

Lead Scientist: Charles Engelbracht

Allocated time: 16.5 hours

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Confirm the absence of warm dust (T < 300 K) in the cores of six high redshift quasars.

Our Herschel key project "The Dusty Young Universe" observed 71 quasars at the highest redshifts (z > 5) with PACS and SPIRE. Similar to the local universe we find that the hottest, AGN heated dust shows a flat or slightly rising spectral energy distribution in nuF_nu between 24mu (Spitzer) and PACS 100mu (i.e. rest-frame 3.4mu < lambda_rest < 14mu at z=6). However, in the course of the project we identified some exceptional cases that are undetected by PACS at 100mu. Their upper limits result in nuF_nu(100mu) < 0.8*nuF_nu(24mu) indicating a deficit of cooler dust below T ~ 300 K. Such cases are not known among AGN in the local universe and seem to require a very compact central dust distribution. Here we propose to re-observe the best six of these exceptional quasars with PACS at 100 and 160mu with a threefold integration time in order to reach a factor of 2 deeper in flux when combining with the already acquired data. Both a successful detection or a substantially lowered upper limit will allow us to determine the temperature of the hot dust better and estimate its total mass. The small radius of the dust distribution might indicate dust production near the quasar core. PACS on Herschel is the unique facility to investigate the apparent differences of the dust distributions in quasars between the young universe and today.

Lead Scientist: Christian Leipski

Allocated time: 15.2 hours

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Feedback from the most luminous dust-obscured AGNs in the universe

AGN-powered feedback of energy and momentum via radiation pressure ("quasar mode") on interstellar dust and jet momentum ("radio mode") from a supermassive black hole (BH) into its host galaxy regulates the evolution of both the BH and the galaxy. Feedback is likely to be strongest in the most luminous dust-obscured QSOs, particularly those containing radio sources too luminous to be powered by starbursts. We selected a unique sample containing 147 of the most luminous obscured QSOs in the universe by identifying strong mid-infrared sources from the WISE survey covering more than half the sky having (1) convex mid-infrared spectra and (2) bright NVSS radio counterparts. The goal of our multi-telescope program is to understand the physical and evolutionary nature of these extreme feedback candidates. We have high priority (top decile) ALMA Cycle0 time for the southern sources in the sample for imaging at 345GHz, and SOAR time to obtain redshifts. This proposal requests 47.6 hours of PACS and SPIRE time to determine the relative warm to cool dust luminosities in these 147 sources, key observations for determining the relative AGN and starburst luminosties, and understanding the evolution stages, of these likely transition objects. Our goals are to discover the most obscured and powerful BHs throughout their main epoch of formation, and to test and constrain the roles of radio and radiative feedback in the quenching of star formation and the establishment of the BH-spheroid relations.

Lead Scientist: Carol Lonsdale

Allocated time: 47.6 hours

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Local Benchmarks for Cosmic Evolution of Major-Merger Pairs -- A Herschel Study of SFR Dust and Gas Content

We propose to map a complete sample of 88 local star-forming major-merger pairs (median redshift 0.04), using PACS and SPIRE photometers in 6 bands at 70, 100, 160, 250, 350 and 500 micron. The goal is to set the local benchmarks for the cosmic evolution of the SFR-to-gas relation (the Kennicutt-Schmidt law) for major-merger pairs, complementing a study on the K-S law for high-z mergers in the COSMOS field using the PEP and HerMES data. The K-S law for major mergers may be significantly different from that for normal galaxies. The SPIRE imaging at 250, 350, and 500 micron, together with PACS maps at shorter wavelengths, will probe the gas mass estimated from the dust mass. Dust is arguably the best proxy for total gas in galaxies spanning a wide redshift range, given the fact that it is still impossible to observe the HI gas in high redshift galaxies through the 21cm line emission. The PACS imaging at 70, 100, and 160 micron will map the star formation in these systems, with good angular resolutions (6 -- 12 arcsec) and at the wavelengths near the peak of the infrared dust emission. The local sample closely matches the high-z COSMOS pairs sample (278 pairs) in the pair selection criteria, both being stellar mass selected and including only spiral-spiral (S+S) and spiral-elliptical (S+E) major-merger pairs. This will facilitate studies on stellar mass dependence of the K-S law for major mergers with different redshifts. The large sample size enables good statistics even after separating the sample into subsamples of S+S pairs and of S+E pairs, and into several mass bins.

Lead Scientist: C. Kevin Xu

Allocated time: 43.2 hours

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Constraining the TP-AGB Contribution to Integrated Stellar Populations With FIR Dust Temperatures

We propose PACS 70um and 160um photometry of 5 post-starbust galaxies selected from the SDSS and detected in the Spitzer MIPS 24um channel. We will measure the temperature of the FIR dust continuum and determine the contribution of enshrouded star formation to the observed 24um luminosity. This measurement, in combination with optical and NIR spectroscopy will allow us to constrain the bolometric contribution of TP-AGB stars to these galaxies. By doing so, we will constrain the TP-AGB as a systematic bias for MIR measurements of star formation and AGN and determine the extent to which TP-AGB stars must be taken into account when inferring stellar masses from observed luminosities and colors of galaxies. The observations will consume 9 hours of spacecraft time for these 5 objects, and we will leverage this time by employing photometry from the Herschel archive for one additional source and considering the impact of 7 other post-starburst galaxies with MIPS upper limits. This gives us a total sample of 13 galaxies to determine the importance of the TP-AGB as a function of burst age and strength and to extrapolate from our sample to a more extensive range in star formation histories.

Lead Scientist: David Atlee

Allocated time: 9 hours

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From dust properties to galaxy evolution: sub-mm observations of counter-rotating galaxies

We propose observations, using SPIRE at 500 micron, 350 micron and 250 micron, of a sample of galaxies showing the phenomenon of counterrotation (gas vs. stars and/or stars vs. stars). Our targets span all the morphological sequence and the sample is composed by all the galaxies with counter-rotation in the local volume of 10Mpc. Our aim is to derive, for the first time, the sub-mm emission of such galaxies. Our simulations of galaxy evolution, that include spectro-photometric evolutionary population synthesis (EPS) accounting for dust effects, are able to predict the whole spectral energy distributions (SED) of a galaxy at different epochs together with the dynamical properties of all the system components. As explained in the following, these new data combined with our model will allow us to constrain the SEDs giving not only insight into the properties of the dust (temperature, mass and distribution) but also the age of the galaxy or the merger that originated the counter-rotation.

Lead Scientist: Daniela Bettoni

Allocated time: 2.1 hours

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The Power Source in IR-luminous Galaxies at 3<z<5: Deep PACS Observations of SPIRE Sources with Spectroscopic Redshifts

We propose to set some of the first robust constraints on the power source in IR-luminous galaxies at 3<z<5, via PACS photometry of ten sources in this redshift range. All of our targets are far-IR selected, have secure SPIRE detections, and spectroscopic redshifts from intensive ground-based followup. None of them are classical QSOs. The 3<z<5 redshift range is a crucial one for understanding the role that IR-luminous galaxies play in driving galaxy evolution. The rates of stellar and SBMH mass assembly must have increased by a factor of at least 5 during this epoch, with a substantial fraction of this increase thought to occur in obscured, luminous `bursts'. Despite this, determining the power source in z>3 IR-luminous systems has been hard; they are difficult to find high spatial resolution counterparts for, and require both mid- and far-IR photometry to deconvolve their SEDs and extract starburst and AGN luminosities. The PACS data proposed for here will be sensitive to even moderately IR-luminous AGN in our sample. In combination with the SPIRE data, which is sensitive to obscured star formation, we will set tight constraints on the power source behind the IR emission in our sample. This, in combination with previous results, will provide important information on the evolution of the power source(s) in IR-luminous galaxies with redshift across most of the history of the Universe.

Lead Scientist: Duncan Farrah

Allocated time: 28.7 hours

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The Dust Mass of the Extremely Metal Poor Galaxy I Zw 18: Imaging at 100 and 160 microns

We will use PACS scan maps to measure the 100 and 160 micron flux of I Zw 18, the lowest metallicity galaxy within 20 Mpc. I Zw 18 offers a nearby window into to the processes which make stars in the primitive galaxies observed in the high redshift Universe. We will measure the dust mass of I Zw 18, and combine this with data already in hand to determine its dust-to-gas ratio, yielding *the* crucial measurement to establish how dust-to-gas ratio relates to metallicity in galaxies. Measuring the dust mas of I Zw 18 requires to accurately constraint of the long wavelength side of the dust infrared spectral energy distribution. Existing data has proven unsuccessful at detecting this galaxy longwards of 70 um. Our observations are designed to detect I Zw 18 at 100 um and either detect it or yield a strong constraint at 160 um. With a very modest time investment (under 5 hours) these measurements will determine whether the dust-to-gas ratio is linear or superlinear with metallicity. Because the dust-to-gas ratio is related to the formation and destruction of molecules and the heating of the ISM, this is a key measurement to understand the impact of metallicity on the evolution of galaxies.

Lead Scientist: David Fisher

Allocated time: 4.9 hours

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Dust and Star Formation at Low Metallicities

Dust affects the cooling cycle in the ISM and this affects the ability of a galaxy to form cold, dense clouds that can form stars. Thus, the low dust content of dwarf irregular galaxies should have consequences to the star formation process, but just what is the connection? We propose to use SPIRE and PACS to map the FIR dust continuum emission of 5 dwarf galaxies, specifically extending the sample of nearby resolved dwarfs being observed under KP/GT/OT1 programs to 5x lower metallicities. We will construct spatially resolved FIR spectral energy distributions and determine the dust components. That, in combination with our exquisite HI maps and comprehensive images tracing star formation over three age scales, will allow us to examine the relationship between the dust content, gas, and star formation in dwarf irregular galaxies as a function of metallicity. These data will be unique in the wealth of information they will provide about dust at very low metallicities, and this will be important for understanding the formation of stars in the early universe.

Lead Scientist: Deidre Hunter

Allocated time: 12.3 hours

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Measuring the duration of star formation in local luminous compact blue galaxies.

Eight billion years ago, at z~1, the star formation rate (SFR) in the universe peaks and the vast majority of galaxies are blue with the plurality being luminous compact blue galaxies (LCBGs). Today, the SFR is an order of magnitude lower, galaxies are evenly divided between a red and blue sequence, and LCBGs are extremely rare. It remains unclear as to what has caused star formation to be quenched in galaxies in general, and specifically in LCBGs. Since LCBGs reside at the high mass end of the blue sequence, they are poised to have their star formation quenched in the near future. As such, they are a unique laboratory for studying how galaxies evolve from the blue to the red sequence. We are proposing to use PACS and SPIRE photometry to measure the SFR and dust mass for 52 local LCBGs in order to constrain the duration of their current starburst. Combined with multi-wavelength archival data, we will identify which LCBGs are having their star formation quenched and determine how these galaxies will evolve.

Lead Scientist: D.J. Pisano

Allocated time: 10.4 hours

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Herschel Spectroscopic Survey of Far-Infrared Fine Structure Lines in intermediate redshift Ultraluminous Infrared Galaxies

Herschel has provided unprecedented insight into the properties of the ISM of local Ultraluminous Infrared Galaxies (ULIRGs) and high redshift submillimetre bright galaxies. Although matched in luminosity the ISM properties of the two samples are markedly different. We propose to exploit the wide wavelength coverage of SPIRE-FTS to study far-infrared fine structure cooling lines from a unique sample of 23 intermediate redshift ULIRGs. Our targets span the redshift range 0.2 < z < 0.8 and luminosity range 12 < log L(IR) < 13 and have been selected from the Herschel Multi-tiered Extragalactic Survey (HerMES) with excellent ancillary data. The redshift range has been chosen so that we can simultaneously detect key cooling lines [CII] 158 microns, [NII] 205 microns and [CI] 371 microns in all of our targets. Our sample is suitably selected to link the properties of the ISM near and far: it is at these intermediate redshifts where the change in the properties of the ISM takes place. Using the proposed observations we will: 1) investigate the properties of the ISM of ULIRGs at a redshift where they contribute dominantly to the total IR energy density; 2) search for changes in the ISM as a function of luminosity and redshift; 3) explore metallicities (through [CII]/[NII] ratio) and investigate the validity of [NII] as a star formation indicator; 4) address the effect of the AGN in the surrounding ISM. To complete our goals we request observations for a sample of 23 ULIRGs. Herschel is currently the only facility capable of addressing these important questions.

Lead Scientist: Dimitra Rigopoulou

Allocated time: 89 hours

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Luminosities and Temperatures of Dust with SPIRE for Most Luminous Quasars to z = 5

SPIRE photometry is proposed for the 156 most infrared-luminous quasars with 1.5 < z < 5 to determine accurate total infrared luminosities and evolution of luminosity and dust temperature. Sources are chosen using new mid infrared measures with the Wide Field Infrared Survey Explorer of quasars from the Sloan Digital Sky Survey. SPIRE will measure all quasars in this redshift range at rest frame 80 micron, near the luminosity peak, and will give full SEDs from rest frame ultraviolet to far infrared when combined with WISE and SDSS data. Results can be compared to existing archival results for the most luminous, heavily obscured, type 2 quasars discovered with Spitzer and contained in Herschel key project survey fields.

Lead Scientist: Daniel Weedman

Allocated time: 14.5 hours

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Excited H2O and OH as tracers of buried activity in the nuclear regions of (Ultra) Luminous Infrared Galaxies

H2O and OH are key tracers of the structure, kinematics, and activity in the nuclear regions of (Ultra) Luminous Infrared Galaxies (ULIRGs): with their excitation dominated by pumping by far-infrared continuum radiation, they probe the nuclear source of the far-IR radiation and its associated structures (disks, torus); their P-Cygni, absorption, and emission profiles trace massive molecular outflows and possibly inflows, and the astrophysically important associated energetics involved in the (negative) feedback from star formation and/or AGN on the molecular gas; they probe the physical and radiative environments (X-rays, cosmic rays, hot cores) where they reside. In order to distinguish among the above scenarios, we propose PACS spectroscopy of key transitions of H2O and OH in a sample of 9 bright (U)LIRGs where submillimeter H2O lines have been detected with SPIRE, as well as key diagnostic lines of NH3 and OH+ to ascertain the formation mechanism and implied physical processes. The proposed observations will serve as a crucial benchmark for future routine observations of H2O with ALMA in the distant Universe.

Lead Scientist: Eduardo González-Alfonso

Allocated time: 38.3 hours

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A detailed anaysis of the [CII] line emission for a large sample of star-forming galaxies at z<0.2

We propose to exploit the spectroscopic capabilities of PACS to describe the [C II] line emission in a unique and comprehensive sample of star-forming galaxies selected from the wide-field, parallel PACS+SPIRE H-ATLAS imaging survey.

The sample has exquisite optical spectra from GAMA and SDSS, allowing us to:

[1] describe [C II] line as a function of dust and stellar mass, metallicity, extinction, dust temperature, and many other physical parameters; [2] identify the parameters controlling the behaviour of [CII]/L(FIR) at log L(FIR)>11; [3] calibrate [CII] as a star-formation indicator [exploiting our accurate L(FIR) and L(Halpha)] and determine the range over which it is valid.

[CII] is potentially an unrivalled tracer of the total gas mass in galaxies (in theory better than CO), and it is therefore an increasingly important observable, e.g. for upcoming ALMA observations of distant galaxies. Our study will become the benchmark for the interpretation of high-z observations, with a legacy value that will survive well into the SPICA era.

Some of the key advantages of this proposal over previous Herschel studies such as SHINING and HerCULES are:

- we cover 10.2 < log L(FIR) < 11.5 and are unbiased towards powerful ULIRGs with complex merger morphologies; - our sample is selected blindly from H-ATLAS rather than from IRAS, and thus allows exploration of comprehensive parameter space and is much less biased towards galaxies with warm dust emission; - we know the spatial extent of the galaxies, allowing reliable flux measurements via a single pointing within 10 min/target.

We can thus achieve our goals in a systematic fashion, maximising the parameter space for the diagnostics of interest.

We stress that the scientific legacy of ISO and Spitzer has in large part been based on the wealth of data in their spectroscopic archives and the same will likely be true for Herschel.

Lead Scientist: Edo Ibar

Allocated time: 13.4 hours

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Dust temperatures in nearby turbulent disk galaxies: evidence for nearby cold flow gas accretion?

We propose a survey of PACS (at 70 and 160 micron) and SPIRE (at 250, 350 and 500 micron) imaging of a sample of 31 of the most turbulent and intensely star forming galaxies in the local universe to measure their characteristic dust temperatures, dust masses and total infrared luminosities. These galaxies, selected from the all sky SDSS survey as the most H(alpha) bright galaxies in the nearby universe, have high velocity dispersions but show signs of ordered disk rotation (Green et al 2010) and as a consequence have more similarities to high-redshift turbulent disk galaxies than dynamically-relaxed galaxies common to the local universe. But are these truly low redshift analogues of turbulent rotating disks or are they currently undergoing a starburst episode? While both galaxy types are expected to be bright in the infrared, the former would have a much lower characteristic dust temperature that can efficiently be measured with Herschel due to the proximity (0.06<z<0.25) of these galaxies.

Lead Scientist: Erin Mentuch

Allocated time: 6.7 hours

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Identifying Ram Pressure-Induced Shocks in Stripped Virgo Spirals

We propose to investigate the presence of ram pressure-induced shocks in three Virgo cluster galaxies exhibiting clear evidence for on-going ram pressure stripping, from a wealth of radio continuum, optical, infrared, and HI data. To achieve our goals, we will perform PACS spectroscopy to measure the [OI] and [CII] emission line strengths of three outer-disk regions. These regions are precisely located along the leading edge of the interaction region between the hot intracluster medium (ICM) and the cooler galaxy interstellar medium (ISM). The ionization state of the ISM gas within the leading edges will be revealed by the ratios of these two emission lines since they are the dominant coolants in the neutral and ionized ISM at low temperatures. Previous Spitzer IRS observations hinted at the presence of shock-excited molecular hydrogen. Hence, these proposed PACS spectroscopic observations will provide independent confirmation of ram pressure-induced shocks in the cold ISM along the leading edges of these ram pressure-stripped galaxies. Evidence for shock excitation throughout the ISM may explain the enhanced, global radio/infrared ratios observed in galaxies that are experiencing strong ram pressure.

Lead Scientist: Eric Murphy

Allocated time: 22 hours

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The Herschel EDGE-on galaxy Survey (HEDGES)

We propose deep PACS and SPIRE imaging for all (6) normal, edge-on (i >85 deg) galaxies with d<10Mpc as part of the Herschel EDGE-on galaxy Survey (HEDGES). These data will allow us, for the first time, to characterize variations in the far-infrared (FIR) spectral energy distribution (SED) among and within halos for an energetically diverse sample of nearby, edge-on galaxies as a function of height above the disk. The proper sampling of the halo dust SEDs (i.e., 6 bands between 70-500um), will allow us to take inventory of the dust content of halos and illuminate the signatures of dust processing imprinted in the dust SED and its variations. These observations will provide a way to address a number of outstanding questions related to the processes governing the interchange of disk/halo material such as: (1) How does halo dust content relate to disk star formation activity? (2) What are the physical characteristics of halo dust (i.e., temperature(s), mass, emissivity, PAH mass fraction, and what does their variation with height from the plane tell us about grain modification by the energetic processes responsible for disk-halo cycling? (3) What can dust and radio continuum halos tell us about transport effects that are important for understanding the FIR-Radio correlation? (4) How does the distribution of halo dust compare to that of other gas tracers, and hence what can we learn about how such dust is associated with various gas phases? The HEDGES sample galaxies have a treasury of ancillary data (e.g., radio, Spitzer, optical, gas), and the addition of these deep Herschel data will make HEDGES the definitive sample to study multi-phase disk/halo feedback processes arising from the accretion, expulsion, and/or cycling of material between disks and halos into the foreseeable future.

Lead Scientist: Eric Murphy

Allocated time: 50.8 hours

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Remnants of Galaxy Group Formation: A Search for Cold Dust in the Leo Ring

The basic theoretical picture of hierarchical structure formation is well supported by observations. Within this scenario, large galaxies assemble from smaller ones, and such mergers are most common in galaxy groups that are themselves in the process of falling into even larger clusters. However, little is known about the ultimate fate of the primordial gas that is used to fuel the formation of these galaxy groups. Does all the metal-free gas get consumed in galaxies and reprocessed? If the gas is left outside of galaxies in the intragroup medium, is it ionized on timescales too short to be detected at the current epoch? Is any left behind pristine and untouched? To answer these questions, which are crucial for a complete picture of galaxy formation and evolution, we propose for confusion-limited mapping of the entire (2 x 2 deg) Leo Ring in all three SPIRE bands to search for cold, low surface brightness dust emission. At 10 Mpc and 200-kpc in diameter, the Leo Ring is the only known HI cloud for which a primordial origin has not been ruled out. A firm cold dust detection would eliminate the possibility of a primordial origin for the Ring. Alternatively, a non-detection would place a strict upper limit on the dust-to-gas ratio an order of magnitude lower than has been observed for nearby low-metallicity systems, and thus would make a tidal origin highly unlikely. If the far-infrared SPIRE flux measurements lead to a conclusion that the gas is primordial, the Ring will be the first known instance of HI gas left unprocessed and not yet ionized after the formation of a galaxy group, and offers a unique snapshot of galaxy formation in action.

Lead Scientist: Eric Murphy

Allocated time: 14.7 hours

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Cold Dust as a Tracer of Molecular Gas in Low Metallicity Galaxies

The assembly of star forming molecular clouds is poorly understood in low metallicity galaxies. These galaxies are typically forming stars, and thus must have molecular gas, yet they almost universally lack direct detections of CO. As an alternate means to trace the molecular component of these systems, we propose to use the PACS and SPIRE instruments aboard Herschel between 100-500 microns to image the cold dust distribution and determine the temperature of the dust in 4 nearby low metallicity galaxies drawn from the VLA-ANGST sample. VLA HI spectral line observations for these galaxies have exceptional spectral resolution (0.65 - 1.3 km/s) which allows us to reliably decompose the spectra into narrow and broad components which have been associated with the cold and warm neutral gas phases. Coincidence of cold dust detected by Herschel with narrow HI spectra will both confirm the existence of a cold neutral medium as well as define the areas most conducive for molecular cloud formation. Combining the proposed Herschel observations with existing HST, VLA, and SPITZER observations will allow us to separate local regions currently forming stars from those which have yet to form them. Understanding the local conditions which are most likely to form molecular clouds is extremely important to the general understanding of star formation, molecular cloud formation, and galaxy assembly/evolution. If our proposed observations confirm that the narrow HI emission is an effective tracer of the more elusive molecular component, then we will have calibrated a method which is generally applicable for all nearby low metallicity galaxies.

Lead Scientist: Evan Skillman

Allocated time: 19.5 hours

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CII and Cold Dust as a Tracer of Molecular Gas in Sextans A

The assembly of star forming molecular clouds is poorly understood in low metallicity galaxies. These galaxies are typically forming stars, and thus must have molecular gas, yet they almost universally lack direct detections of CO. As an alternate means to trace the molecular component of these systems, we propose to use the PACS and SPIRE instruments aboard Herschel to observe both the 158um CII emission line and the cold dust emission between 100-500 microns in the nearby low metallicity galaxy, Sextans A. Recent VLA HI spectral line observations of Sextans A have exceptional spectral resolution (1.3 km/s). This high velocity resolution allows us to reliably decompose the spectra into narrow and broad components which have been associated with the cold and warm neutral gas phases. Coincidence of 158um CII and cold dust emission detected by Herschel with narrow HI spectra will both confirm the existence of a cold neutral medium as well as define the areas most conducive for molecular cloud formation. Combining the proposed Herschel observations with existing HST, VLA, and SPITZER observations will allow usto separate local regions currently forming stars from those which have yet to form them. Understanding the local conditions which are most likely to form molecular clouds is extremely important to the general understanding of star formation, molecular cloud formation, and galaxy assembly/evolution. If our proposed observations confirm that the narrow HI emission is an effective tracer of the more elusive molecular component, then we will have calibrated a method which is generally applicable for all nearby low metallicity galaxies.

Lead Scientist: Evan Skillman

Allocated time: 25.7 hours

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Constraining the Molecular Outflows in Hyper-Luminous Infrared Galaxies

Simulations of structure formation and evolution suggest that feedback is critically important to the evolutionary paths of galaxies and their supermassive black holes. However, while high velocity outflows have been routinely detected in the ionized winds of many powerful AGN, it remained unclear whether this momentum was being effectively transferred to the neutral and molecular gas that actually form stars. Several recent observations over the past year have finally provided some breakthroughs in this regard: in particular the neutral NaD and molecular OH and CO components in the warm quasar-dominated merger Mrk 231 have all been shown to have >1000 km/s outflows from the nucleus, indicating momentum transfer well in excess of what could be produced by the ongoing star formation alone. Several more ULIRGs are under similar investigation to broaden these important results and understand how this feedback might scale with relative AGN strength, merger stage, availability of fuel, etc. Somewhat surprisingly, these samples include none of the most powerful (i.e., ``hyper'') luminous infrared galaxies (HLIRGs). ``Local'' HLIRGs are 3-10x more powerful than Mrk 231 and their bolometric output is almost always AGN-dominated. As such, HLIRGs can extend studies of how AGN power affects feedback by an order of magnitude. Here we propose to look for trends between the basic measured properties of OH (incidence of absorption, kinematics, column densities) and host/evolutionary indicators in a sample of 5 powerful HLIRGs.

Lead Scientist: Franz Bauer

Allocated time: 28.9 hours

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HIFI observations of carbon in the Magellanic Clouds: sampling low-metallicity ISM physics

Stars form in dense, cold clouds of molecular hydrogen (H2), best observed in lines of the tracer carbon monoxide (CO). As stars turn on, the dense gas is heated, ionisation occurs, and a photon-dominated region (PDR) is formed. Here, CO dissociates to neutral carbon, much of which is subsequently ionized. Both neutral and ionized carbon cool the interstellar gas by strong line emission at far-infrared/sub-millimeter wavelengths. Thus, CO emission is a good tracer for cold and dense, [CI] for warm dense, and [CII] for warm tenuouis gas. Cold tenuous gas is traced by neutral atomic hydrogen emission.

Galaxies have different metallicities and gradients, strongly affecting the physical processes ruling the heating and cooling of the interstellar medium (ISM). In order to understand the ISM in distant galaxies, we need to understand how metallicities and radiation fields affect ISM physics. By observing the ISM in the low-metallicity Large and Small Magellanic Clouds, the response of the ISM to various radiation fields is gauged as a function of the very different metallicities of the SMC, the LMC, and the Milky Way.

We have selected in the LMC and the SMC interstellar clouds exposed to a range of radiation field intensities. Ideally, we would fully map these clouds, but time constraints limit us to strips in lines requiring long integration times: the 1.9 THz [CII] and 809 GHz [CI] lines, which are in effect unobservable from the ground, requiring Herschel space-borne observations, to complement a series of CO and [CI] (492 GHz) observations from the ground. Together with HI maps, they will provide us with the carbon and hydrogen budgets, and determine, in detail, the distribution of the various carbon phases over a wide range of phyical conditions. Analysis of the HI/[CI]/[CII]/CO/H2 interfaces is well-feasible thanks to the advanced ISM/PDR codes developed by members of our team.

Lead Scientist: Frank Pieter Israel

Allocated time: 37.3 hours

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Measuring the Far-infrared SED of Cygnus A

The powerful radio galaxy Cygnus A affords the opportunity to study the activity of a hidden quasar at high spatial resolution. We have modelled the optical through radio SED of Cygnus A using data from a dedicated Spitzer spectroscopy program (Privon et al 2011). Our primary aim was to constrain the relative contribution of AGN and star formation heating to the total energy budget of the source. Our analysis also reveals that there must be a break in the synchrotron spectrum at FIR/sub-mm wavelengths. However, the paucity of data from 70-500 mu limits our ability to define the synchrotron component and the physical decomposition of the SED. We propose a 3hr program of observations with PACS and SPIRE to precisely define the far-infrared emission of Cygnus A between 50 and 700 microns. This will provide tight constraints on the far infrared emission and enable us to accurately model the contirbution of embedded star formation to the infrared luminosity. This in turn will provide an improved determination of the bolometric AGN luminosity, the geometric properties of the obscuring torus, and the behavior of the synchrotron spectrum at infrared wavelengths. We have in place a comprehensive suite of Bayesian SED modelling codes to analyse the data.

Lead Scientist: George Privon

Allocated time: 3.2 hours

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Herschel Among the Early Types: cold dust in dead galaxies

The Herschel Reference Survey (HRS), the first unbiased survey of dust in early-type galaxies (ETGs), has provided insights into the evolution of both S0s and ellipticals. The small dust disks in S0s suggest that these galaxies are early-type spirals that have had their dust and gas removed by environmental processes such as ram-pressure stripping. The properties of the dust in the ellipticals imply that the dust in these has been acquired by gravitational interactions - a process that is likely to be more important in low-density environments. Although the optical properties of ETGs do not depend strongly on environment, in contradiction to the hierarchical paradigm, our results suggest that there should be a clear environmental signature in the properties of the dust. The volume of the HRS, however, is dominated by the Virgo Cluster, and so contains few ETGs in genuinely low-density environments. As a collaboration between the HRS and ATLAS3D teams, we propose to carry out an efficient Herschel survey of the much larger ATLAS3D sample, providing a legacy survey of four times as many ETGs as are in the HRS and extending our original survey to much sparser environments. Apart from its legacy value, we will answer four questions: 1) Are the small sizes of the dust disks in S0s the result of a current environmental process? 2) How do the properties of the dust in ETGs depend on the mass of stars in the galaxy? 3) Do the dust properties of the ellipticals display the clear environmental signature that the hierarchical paradigm requires? 4) How do the dust properties of the ETGs depend on the specific angular momentum of the stars, which has been measured for the ATLAS3D galaxies and may be more revealing of the basic physics of ETGs than the morphological classification of ellipticals and S0s?

Lead Scientist: Haley Gomez

Allocated time: 45.1 hours

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Spatially-resolved study of dust grains in X-ray elliptical galaxies to understand their origin and interplay with hot plasma

We propose to study the properties of dust in elliptical galaxies. The interstellar environment of elliptical galaxies is characterized by the dominance of hot plasma and old stellar radiation fields with little UV. Dust in hot plasma is easily destroyed by sputtering, while old stars cannot replenish a large amount of dust into the interstellar space. Despite such hostile conditions, many elliptical galaxies contain a considerable amount of dust. Our goals are to identify the supplying sources of dust and to understand interplay between dust and hot plasma. We selected 6 galaxies from the AKARI sample, which were found to be extended in the far-IR with AKARI. But its spatial resolution was too poor to discuss the detailed structures of the dust emission. Herschel is the only facility which enables us to discuss them. Our studies are based on two kinds of Herschel data: PACS imaging with the finest resolution and PACS-SPIRE SED mapping with a coarser resolution. Using the former data, we spatially decompose the dust distribution into a stellar distribution, a dust lane, a central point-like source, and the other. We derive the fraction of each component to the total emission. The last component may represent clumpy clouds in outer regions or structures extending from the center, which are compared with X-ray data. As for the latter data, we combine them with the AKARI mid-IR images to obtain SED maps. Each SED will be compared with model SEDs to investigate the dust size distribution and temperature. From spatial variations of the size distribution, we determine the dynamics of dust, i.e., in-falling to or out-flowing from the center of a galaxy. Finally the results of both studies will be combined to draw a firm conclusion on the origin of dust in elliptical galaxies. The proposed observations have exposure deep enough to detect diffuse emission associated with each galaxy, which are complementary to those so far performed with rather shallow exposure for a larger sample of elliptical galaxies.

Lead Scientist: Hidehiro Kaneda

Allocated time: 8.9 hours

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Star formation in the most luminous local LINERs

LINERs are the most common AGNs in the local universe but their FIR properties are only poorly known. It is believed that most such nuclear emission line regions are situated in hosts with old stellar population and are different from high ionization Seyfert galaxies that show much higher star formation rate (SFR). Recently we found, using Herschel/PACS, that this is not the case in a sample of z=0.3 LINERs that are more luminous than the best studied local LINERs. Many of these sources show L(FIR) as large as 10^11 Lsun and their H-alpha line is extremely week suggesting unusual extinction or a decaying starburst. This proposal suggests a systematic Herschel/PACS study of the most luminous 0.05<z<0.11 LINERs, comparable in their L(AGN) to the z=0.3 LINERs. There are 49 LINERs in this sample and we divided it into two groups according to the distribution of the UV continuum (Galex) light (``nuclear'' and ``extended'' LINERs). We will be able to 1. measure L(IR) of 10^10 Lsun or larger, 2. compare the FIR luminosity with L(H alpha) to derive the extinction properties, 3. check the validity of D4000 as a sSFR indicator, 4. look for the signature of a decaying starburst and, in general, make a detailed analysis of the FIR-based SF properties of this population that are still completely unknown.

Lead Scientist: Hagai Netzer

Allocated time: 19.4 hours

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Star Formation and Black Hole Growth from z=4.8 to z=2.4

This is the second of a two part Herschel project to follow star formation (SF) in intervals of about 700 Myrs, in host galaxies of the most massive black holes (BHs). The first part, which includes 40 AGNs at z=4.8 (t(Universe)=1.2 Gyrs), has been granted time in OT1 and is already providing spectacular results: SFR as high as any observed before, including the most luminous SMGs, and L(SF) way above the prediction of the standard L(AGN)-L(SF) correlation. The present part focuses on the most luminous AGNs at z=2.4 and z=3.5. The z=3.5 group is a flux limited optical sample of the most luminous AGNs. The one at z=2.4 contains 42 BHs with known masses measured by the most reliable Hbeta-based method. The combination of the samples, that are likely to represent three stages in the evolution of the most massive BHs, will allow us to answer several fundamental questions related to the connection between SF and BH activity. 1. What are the relationships between L(AGN) and L(SF) at z=4.8, 3.5 and 2.4? 2. What fraction of the hosts of the most luminous AGNs have already finished, or substantially reduced, their accumulation of stellar mass at every redshift? 3. Can we infer the accumulation of stellar mass through the two periods of about 700 Myrs, and hence the SF duty cycle, assuming these sources will become the most massive galaxies in the local Universe? The z=2.4 sample will be observed with both PACS and SPIRE and the z=3.5 sample only with SPIRE. The total requested Herschel time is 46.4 hours.

Lead Scientist: Hagai Netzer

Allocated time: 17 hours

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Merger driven vs. Cold-flow driven Star Formation in

One of the biggest challenges in galaxy evolution is to understand how star formation is powered in high-redshift star-forming galaxies. Recent discovery of unusually strong (EW > 500A) Halpha emission in majority of z>4 star-forming galaxies has provided indirect evidence that significant fraction of high-redshift star formation is fueled by mechanisms other than gas-rich merger, suggesting that cold gas accretion is an important source of cold, neutral gas in high-redshift galaxies. FIR cooling lines such as [CII] 158 micron line, produced by the UV stellar radiation like Halpha, afford an efficient probe to study physical properties of the interstellar medium in star-forming galaxies. Therefore, we propose to observe [CII] emission line from local counterparts of high-redshift strong Halpha Emitters to investigate the properties of cold neutral gas in these galaxies and understand how star formation is powered. We request total 11.1 hours of Herschel/PACS observation using Line Spectroscopy AOT for 20 targets, detecting the expected [CII] line with line S/N of >3. Unlike the IR-luminous galaxies or QSOs, HAEs are typical star-forming galaxies at high redshifts thus [CII] observation of local HAEs would provide the first measurement of [CII] and [CII]/FIR ratio of typical high-redshift star-forming galaxies. Thanks to the existing data including spectroscopy, the relationship between the observed [CII] and Halpha, FIR luminosity can be investigated as a function of metallicity, stellar population, extinction, etc. Such relationship would be able to tell whether [CII]/FIR ratio can be used as an indicator that discriminates merger-driven star formation and cold-flow driven star formation. Using the last opportunity of Herschel to access rest-frame FIR cooling lines of local galaxies, this observing program would provide a detailed physical framework for interpretation of future large [CII] surveys in galaxies at higher redshifts using existing or planned submm to radio facilities.

Lead Scientist: Hyunjin Shim

Allocated time: 11.1 hours

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Probing the multi-phase outflows in the `Fire and Ice' galaxy IRAS F00183-7111 using far-IR PACS spectroscopy

IRAS F00183-7111 is possibly the most luminous ULIRG discovered by IRAS. Nicknamed the 'fire and ice galaxy' since its widely-cited first Spitzer-IRS observations were published in 2004, this galaxy has continued to amaze. Not only does it host the possibly most deeply obscured powerful AGN/quasar in the Local Universe (z<0.4), its extremely wide mid-IR neon line profiles and the extended red wing to the CO(J=1-0) line hint at massive outflows. These outflows may be powered by the radio jets, which appear to be young and which may be responsible for the optically-obscured, highly disturbed ionized neon gas line emission seen with Spitzer, the multiple spatial and kinematic [O III] 5007A components, and the off-nuclear soft X-ray bubble seen by XMM.

So far this luminous z=0.328 merger has remained unobserved by Herschel. Here we propose to study its nuclear outflow at far-infrared wavelengths to reveal optically obscured high-velocity ionized gas outflow components, and to assess the extent and timescale of the neutral and molecular gas outflows, which may drive the evolution of IRAS F00183-7111 from a deeply buried merger remnant to a naked QSO. Our proposed observations may also benefit existing Herschel ULIRG outflow studies by providing measurements for a ULIRG that will extend the current L(AGN) range by a factor of two. This study will further also be relevant for understanding the population of deeply obscured radio galaxies found at high redshifts.

Lead Scientist: Henrik Spoon

Allocated time: 14.9 hours

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Herschel study of the ISM in Local Group dwarf ellipticals

Taking into consideration that dwarf galaxies are by number the dominant population in the current Universe and are considered as the main building blocks for more massive galaxies, studying their origin and evolution allows putting strong constraints on cosmological parameters. Especially, the ISM of metal-poor dwarf galaxies provides an interesting laboratory to study the outcome of stellar feedback and the effect of this metal-enrichment on future star formation. Since dwarfs with a low metal abundance are the best present-day representatives for the conditions in the early Universe, they offer the best opportunity to learn more about the evolution of this galaxy type throughout the history of the Universe. In particular, the proximity of the Local Group enables spatially resolved studies of the lowest surface brightness dwarf galaxies and benefits from a wealth of available ancillary data.

NGC 205, NGC 185 and NGC 147 are three metal-poor dwarf elliptical companions of M31, featuring a ten times less massive gaseous component than predicted from theoretical star fomation models. Either efficient supernova feedback or the presence of a more diffuse ISM component are thought to be responsible for the missing ISM problem.

We propose to probe the ISM through the continuum emission from dust, to better constrain the ISM mass. Recent Herschel observations for NGC 205 confirm the missing ISM problem in this galaxy. We propose to probe the ISM in NGC 185 and NGC 147 with Herschel. With a dust mass detection limit of ~10^2 Msun, SPIRE observations are considered capable of detecting the ISM in NGC147 for the very first time. The unprecedented resolution at PACS wavelengths allows spatially resolved studies of the dust heating mechanisms, dust characteristics (temperature, composition, distribution) and its correlation with the gaseous component, which well shed light on the typical star formation conditions and, in this way, allow a better understanding of their origin and evolution.

Lead Scientist: Ilse De Looze

Allocated time: 4.5 hours

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NGC604: a resolved extragalactic HII region the link to Galactic star formation

We propose to use HIFI, PACS and SPIRE spectroscopy to study the second most luminous HII region in the Local Group: NGC 604. This proposal is a follow-up of the HerM33es OT-KP on M33 which already observed the FIR continuum of NGC 604 at 100, 160, 250, 350, and 500microns. It is also an extension of Galactic observations, particularly high-mass sources of the Water In Star-forming regions with Herschel (WISH) program.

Because of its proximity, high star formation rate, extreme youth, angular extent, and extragalactic location (which removes projection-effect ambiguities), NGC604 offers a unique laboratory for: (1) investigating the density and temperature distribution of the cold gas by modeling the CO ladder; (2) determining the role of dense gas in the star formation efficiency, and (3) provide a link between the Galactic and local low-J studies and high-z, high-J studies through a source that closely resembles a scaled-down starburst.

The detailed study proposed here will enable an in-depth comparison with both Galactic regions of massive star formation (same lines, convolution of Galactic data to same linear scale) and those in nearby galaxies, particularly the LMC. The metallicity of NGC604 is intermediate between that of 30 Dor (the most luminous HII region in the Local Group) and that of the Galaxy. M33, as a chemically young galaxy but well-defined "normal" spiral, provides an important stepping-stone towards the very young irregular systems (i.e. the Magellanic Clouds). In addition to a HIFI CII strip (as in HerM33es), water lines at 557, 752, 9088, and 1097 GHz (latter 3 seen in emission), PACS will cover the entire HII region in the CII[158], OI[63,146], NII[122], NII[205], NIII[57], and OIII[52], while the fully sampled SPIRE spectroscopy will obtain the full CO ladder and CI lines to complement our high-resolution ground-based low-J CO and HI data.

The present study will have long-term legacy value as a unique study of an extremely luminous HII regions mapped at high resolution.

Lead Scientist: Jonathan Braine

Allocated time: 12.6 hours

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Separating a Galactic Fountain from Galactic Accretion in NGC 891

Galaxies grow by accretion of gas in addition to mergers, but the current accretion rate onto a typical spiral is highly uncertain, with values from a few Msun/yr to less than 0.1 Msun/yr. Gas can accrete hot and we observe X-ray emitting gas as well as HI extending several kpc above the plane around some spirals. This may be a hot accretion mode or it may be a galactic fountain, which can be differentiated by metallicity, the fountain having a near-solar value while accreted gas would be 0.1-0.3 solar. Metal absorption lines are detected against a background AGN projected 5 kpc above the disk of the edge-on spiral NGC 891, but due to opacity effects and the unknown depletion factor onto grains, the metallicity is uncertain. Critical metallicity constraints will result from the proposed PACS spectroscopic observations of the C II and OI emission lines in this same region of the halo and in one other region 12 kpc from the disk. These spectra will determine the metallicities of the gas, revealing if the halo region is accreted material, galactic fountain gas, or a combination.

Lead Scientist: Joel Bregman

Allocated time: 7.2 hours

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The High Velocity Clouds Around the Andromeda Galaxy

Extensive HI studies of M31 reveal 16 clouds of gas with masses around 3E5 Msun and projected distances of 5-30 kpc. Relative to M31, most clouds have radial velocity differences of 200-300 km/sec, which is interpreted as infall onto the galaxy. Little is know of these clouds, but we are in a position to change that with Herschel spectral observations. Through the proposed PACS C II and O I emission line observations, we can determine the heating of the cloud, its abundances, and its temperature. The abundances inform us of the enrichment of this accretion material, while the temperature, along with the density inferred from the HI data, yields the pressure. These clouds are probably in pressure equilibrium with a hot halo, which is only detectable from X-rays at smaller radii. Therefore the cloud pressure gives us the density of the hot halo and the baryon contribution of this extended hot medium. Finally, we can determine whether the HI clouds are heated through an interaction with the hot halo or only by the photon field of the galaxy.

Lead Scientist: Joel Bregman

Allocated time: 8.1 hours

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Far-Infrared Full Spectroscopic Signatures of the Massive Molecular Outflows in the (U)LIRGs Mrk 231 and NGC 6240

One of the exciting new results of the Herschel mission is the discovery of massive, high velocity (v ~ 1000 km/sec) molecular outflows in ultraluminous infrared galaxies (ULIRGs). These outflows, powered by stellar processes or by AGN, are so far, best traced by radiatively pumped far-IR OH transitions and are observed in numerous transitions as P-Cygni, absorption, or emission line profiles. Based on our modeling of the lines and continuum, the OH observations imply short gas depletion times, mass loss rates at least several times higher than the star formation rates, and appear strongest in AGN dominated ULIRGs. These mergers of gas-rich galaxies have been caught in the act of dispersing their star-forming molecular fuel as they evolve toward becoming massive, gas-poor ellipticals! Are these outflows driven by radio jets or radiation pressure due to a partially buried AGN or are compact super-starburst winds carving out a view to a previously hidden AGN? We and others have tuned Herschel PACS spectroscopic scans to one or more OH lines in surveys of infrared-bright galaxies to combine with modeling efforts to derive the parameters of these winds. However, in order to help understand the excitation and radiative effects producing these winds and thus to better ascertain the nature of the driving source(s), we propose to fill in the gaps and thus obtain full PACS spectral scans of two key outflow sources: Mrk 231, a broad absorption line (BAL) quasar, and NGC 6240, a close pair of X-ray luminous AGN. The PACS spectral resolution and sensitivity will enable unprecedented understanding of the outflow mass-loss rates, energetics, and the radiative environments to which their ISM is exposed, based on velocity-resolved line profiles of multiple excited level transitions of OH, H2O, CO, OH+, H2O+, and other molecules. A key goal of this program is to provide foundations for the modeling and understanding of the now numerous Herschel OH outflow surveys of ULIRGs.

Lead Scientist: Jacqueline Fischer

Allocated time: 18 hours

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The Nature of Star Formation in the Nearby Spiral Galaxy NGC 300

Recent studies have found that the star formation rate in local Galactic star forming regions is proportional to the amount of dense gas present in the respective regions, once a minimum extinction threshold is surpassed. However, based on the fact that local Galactic star formation represents a relatively small sample of star formation in our own Galaxy and due to the inherent difficulties in obtaining measurements of a larger volume of the Galaxy, the best way to confirm and improve on this result is to observe the star formation rates and the corresponding amounts of dense material over an entire external galaxy. While systematic millimeter-line observations of dense molecular material in an external Galaxy will have to await ALMA, we have started a project to already obtain detailed studies of the infrared luminosities and star formation rates of individual resolved star forming regions in the nearby spiral galaxy NGC 300, using Spitzer, GALEX, APEX, SMA, and ground-based Halpha data. NGC 300 is the most nearby spiral galaxy at southern declinations and thus an ideal ALMA target. We are currently in the process of obtaining total molecular masses of the HII regions in this galaxy from APEX CO observations while constraining the star formation rates with Spitzer, GALEX,and Halpha data. Here we propose to obtain unbiased mapping of the entire galaxy in both the PACS and the SPIRE far-infrared and submillimeter bands. This will provide a) an unbiased way to find and identify giant molecular clouds in this galaxy and obtain their masses, b) much better spectral energy distributions of the HII and other star forming regions and c) improved star formation rates for these regions.

Lead Scientist: Jan Forbrich

Allocated time: 3.3 hours

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Molecular outflows in the most luminous ULIRGs

One of Herschel's most important legacies will be the detection and systematic study of large-scale molecular outflows. Galaxy outflows are a key ingredient in galaxy evolution: they regulate the growth of galaxies reducing the amount of molecular gas available for star formation, contribute to establish the observed correlation between the black hole mass of a galaxy and the stellar velocity dispersion of its bulge, and play a critical role in the morphological transformation of gas-rich mergers into ellipticals. Before the launch of Herschel, our knowledge of the properties of galactic outflows was mostly limited to the study of the ionized and neutral atomic gas. Little was known about the amount of molecular gas involved in the outflows, its velocity structure and spatial distribution. Herschel revolutionized this field. Since 2009 our group has discovered powerful molecular outflows in the majority of the ultraluminous infrared galaxies (ULIRG) studied. These outflows can be easily identified in the form of strong blue-shifted absorption and red-shifted emission P-Cygni profiles in the OH 119, 79 and 65micron lines. The outflows in some of these galaxies have maximum velocities >1000km/s, mass outflow rates several times larger than the SFR in the galaxy, and molecular gas depletion times <10Myr. Objects with higher AGN luminosity appear to have higher terminal outflow velocities and shorter gas depletion timescales, which indicates that the molecular outflows in these systems might be mostly driven by the AGN. Here we propose to complement current Herschel molecular outflow studies observing a sample of 10 ULIRGs selected among the most IR luminous objects in the local Universe. We will use the redshifted OH 119micron doublet for this purpose. These observations will extend to higher SFR and AGN luminosities the outflow trends found in our previous studies and will be an excellent comparison sample for future ALMA high-redshift observations of the same line in objects with similar IR luminosities.

Lead Scientist: Javier Gracia Carpio

Allocated time: 30.2 hours

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The ``Over-Cooked'' ISM of Starburst Ring Galaxies

Studies of evolved systems like AM0644-741 and Cartwheel find the ISM in the starburst rings to be overwhelmingly atomic despite conditions (e.g., pressure and ambient far-UV fields) clearly favoring a dominant molecular component. Moreover, the local molecular fraction anti-correlates with SFR/area, yielding unusually high star formation efficiencies (SFE) and a highly peculiar star formation law. AM0644-741's starburst ring moreover appears mostly stable gravitationally (Q = 2-6). We have argued that these all follow naturally from the ISM's >100 Myr confinement time in the ring, which amplifies the destructive effects of embedded OB stars and SNe, producing an ``over-cooked'' ISM, i.e., one characterized by small H2 clouds, and a large photo-dissociated HI background. Due to reduced dust columns, H2 is poorly traced by CO rotational lines, and we expect a large ``dark'' molecular component in the ring. We will use PACS and SPIRE photometry with existing IRAC and MIPS data to (1) construct infrared-submillimeter SEDs for the rings of AM0644-741 and Cartwheel to determine the total mass and distribution of H2 by its dust emission following Israel (1996) and Leroy et al. (2009), (2) re-evaluate their peculiar SFE, non-Schmidt star formation laws, and gravitational stability. Not finding a large hidden H2 component would imply that star formation is triggered by other processes (e.g., collisions) at unusually high SFE.

Lead Scientist: James Higdon

Allocated time: 2.7 hours

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Molecular Ions in Galaxies. Tracing the diffuse molecular component

We propose to use HIFI to observe a complete set of molecular ions related to the PDR-XDR-CRs chemistry toward seven galaxies covering all types of activities. We have selected the hydrides CH+, CH, OH, H2O+, HCl, OH+ and H3O+, and the high density tracers HCN, HCO+ and HNC suggested to be affected by X-ray and shock induced chemistry. To cover a wide range of nuclear activity we will observe three ULIRGs, Arp 220 (cold), NGC4418 (warm) and Mrk231, one LIRG, Arp 299A, the AGN NGC1068, and two starbursts, M82 and M83. The high spectral resolution provided by HIFI will be fundamental to disentangle the complex line profiles (usually P Cygni) often observed in galaxies due to clouds observed along the line of sight with different velocities and large changes in the molecular abundances ratios. The H2O, OH+, H2O+ and H3O+ abundances and abundance ratios will be used to disentangle the CR/Xray and the PDR components in the galaxies.

Lead Scientist: Jesus Martin-Pintado

Allocated time: 44.5 hours

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The first insight into the gas properties of a host galaxy of gamma-ray burst 980425

Long-duration gamma-ray bursts (GRBs) have been found to be associated with violent and luminous supernovae. Such massive stars have very short lifetimes and therefore GRBs pinpoint the location of galaxies that have recently undergone an episode of star-formation. Hence, GRBs may provide a promising means of identifying and studying star formation in the Universe. Here we propose to critically assess this issue using the determination of the gas excitation state for the closest GRB host galaxy. This is crucial because GRBs are potentially excellent tracers of the global star formation history, which is of fundamental importance to our understanding of galaxy formation. However, this kind of study requires prior detailed investigation of GRB host galaxies, which has not been fully addressed yet. GRB 980425 associated with SN 1998bw is the closest known GRB (redshift z=0.0085), therefore it is an excellent laboratory for detailed GRB studies. The interplay between dust thermal emission, radio emission and star-formation is not yet well understood even in the closest known GRB host. Moreover, the properties of molecular gas are very poorly understood for GRB hosts, since none of them was detected spectroscopically in the far-IR. Herschel will provide an important step forward with both of these issues. Here we propose a detailed study of the closest known GRB host. From the CO, CII and OI lines of the host of GRB 980425 we will determine its ionisation state. This will lead to an understanding of whether the GRB 980425 host can be regarded as a normal star-forming galaxy, or its star formation rate is enhanced. This will have consequences for interpretation of GRBs as tracers of star formation in the Universe.

Lead Scientist: José María Castro Cerón

Allocated time: 5.1 hours

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Large-scale dynamics and the formation of clouds and stars in the 30 Doradus region of the Large Magellanic Cloud

Understanding the processes governing the formation of clouds and stars in merging systems is key for the study of how galaxies evolved in the early Universe. The 30 Doradus region in the low-metallicity Large Magellanic Cloud (LMC) is the nearest example of this process, resulting from the interaction between the LMC and the halo of the Milky Way. This makes 30 Doradus the prime laboratory to study these large-scale dynamical processes under conditions that are similar to those at early cosmological times. We propose to use Herschel to obtain a large-scale uniform sampling of this region in [CII] 158um, [NII] 122um and 205um, and [OI] 63um and 146um lines with PACS, and at selected positions in [CII] with HIFI. With this data we will derive the large-scale distribution of the density and pressure of the low-metallicity gas revealing the characteristic signatures of shocked gas. This will then be used to determine the relationships among the diffuse, "dark H2", and dense molecular gas in the 30 Doradus region. We will also derive the electron density distribution of the gas and from this the contribution from ionized gas to the observed [CII] emission. The proposed observations will allow us to study the effect of large-scale gas compression in the multiphase, low-metallicity interstellar medium of 30 Doradus. This information will be valuable for the interpretation of future observations of [CII] in high-redshift galaxies made with ALMA

Lead Scientist: Jorge Pineda

Allocated time: 68.5 hours

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Cold Dust in the Ejecta of Two Nearby Supernovae: Are supernovae dust producers in the early Universe?

Recent Herschel observations have detected up to 0.7 Msun of cold dust surrounding SN 1987A . This discovery implies that supernovae could be responsible for the large dust masses detected in high red-shift galaxies and opens opportunities in the Herschel era for detecting and measuring accurate cold dust masses in extra-galactic supernovae. One data point from SN1987A is insufficient to resolve the fundamental question of the origin of dust in early Universe, therefore we propose Herschel PACS and SPIRE imaging observations of the two nearby supernovae SN 2004et and SN 2004dj. After SN 1987A, they are the closest well-known supernovae with evidence of dust formation from Spitzer and other ground-based observations. Our scientific goals are i) to detect far-infrared and submm emission from supernovae, ii) to understand the spectral energy distribution of the SNe for temperatures and dust composition, and iii) to estimate freshly formed dust mass. These added observations are essential to help determine if supernove are significant dust makers in the early Universe.

Lead Scientist: Jeonghee Rho

Allocated time: 6.7 hours

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How do Compton-thick AGN reprocess their energy?

At present, though we suspect that highly obscured AGN may play a major role in the infrared background and the evolution of galaxies, we have a poor empirical measure of the intrinsic spectral energy distributions of dust-obscured AGN. It is presumed that the obscured X-ray and UV photons are re-emitted in the infrared, but with what SED shape? How important is very hot dust versus very cool dust? What does the SED say about the circumnuclear structure, compared to unobscured AGN? To address these questions, we propose PACS/SPIRE 60-500 micron imaging of five nearby Compton-thick AGN, which we will combine with an additional four targets already in the Herschel archive. We will combine this dataset with our existing dataset from Spitzer to create high--quality 5--500 micron SEDs. This will help us understand how AGN obscuration works in the nearby universe, and will provide templates to apply to higher redshift to better understand the cosmological importance of buried accretion and its contribution to the infrared and X-ray backgrounds.

Lead Scientist: Jane Rigby

Allocated time: 2.1 hours

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After the Fall: Probing Dust and Gas in Post-Starburst Galaxies with Herschel

To explain the nature of galaxies in the present day universe, contemporary models of galaxy evolution require feedback to expel a substantial fraction of the gas and dust fueling stellar and black hole growth, thereby driving galaxies into quiescence. Post-starburst galaxies are systems found precisely in this phase -- after star formation has been abruptly halted. Due primarily to lack of sample and sensitivity, however, the dust and gas content of post-starbursts has remained essentially an unknown. Until recently very challenging to find and study, large samples of close to one thousand post-starbursts can now be selected using the combined power of SDSS and GALEX.

We propose targeted follow-up of a sample of 33 post-starbursts, carefully selected to sample uniformly a wide range of precisely determined post-burst ages, from 50Myr to 1.5Gyr. To construct this sample, we have powerfully extended our unique UV/Optical selection using pre-release WISE full-sky photometry, which provides critical sampling of their mid-infrared SEDs. With PACS and SPIRE photometry extending SED coverage beyond the dust emission peak, and PACS spectroscopy in the dominant gas cooling lines [CII] and [OI], we can begin to address the question of how and why galaxies stop forming stars and fade into quiescence.

Herschel alone can provide the vital, unique information on the conditions and content of neutral gas and dust in galaxies during this crucial transitional phase in their evolution. Our program will 1) characterize the ISM content in these systems as a function of post-burst age, 2) search for clues identify their quenching mechanisms, 3) explore the form and behavior of dust in unique and extreme environments, and 4) test the laws governing star formation and the flow of energy through the ISM in a wholly new regime -- where gas and dust are plentiful, but where star-formation has recently and abruptly ceased.

Lead Scientist: J.D. Smith

Allocated time: 52.8 hours

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Towards a Resolution of Uncertainties in Calibrating Nebular Abundances

We propose to measure the far-infrared (FIR) [O III] transitions in several extragalactic HII regions with the goal of understanding the proper calibration of gas phase oxygen abundances. Despite being a key attribute that influences galaxy evolution, the absolute scale of nebular abundances are highly uncertain (0.7 dex). This uncertainty is rooted in the limitations of optical emission lines that are strongly affected by temperature variations and extinction. With Herschel we have the ability to solve this long standing calibration uncertainty. To this end we propose observations of HII regions in nearby galaxies that will complement Herschel [O III] observations by Herschel Open Time Key Projects and allow complete coverage of the range of metallicities present in the local universe. High quality optical spectra already exist for all of the targets we propose. Thus, we have an unprecedented opportunity to finally calibrate the chemical abundance scale across several decades of metallicity using the PACS spectrometer on-board Herschel. The FIR is a critical wavelength regime that has never been visible with the resolution possible to begin matching measurements with long-slit optical observations. This is a unique opportunity to constrain chemical evolution models and the enrichment history of the local universe.

Lead Scientist: Kevin Croxall

Allocated time: 15.3 hours

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The role of AGN feedback in increasing the turbulence of the molecular gas: lessons from the warm phase

Feedback mechanisms, i.e., jets, winds, and radiation pressure from active galactic nuclei (AGN) are thought capable of suppressing or triggering star formation in their host galaxies. Their past occurrence might have even affected the observed luminosity functions of present-day galaxies. AGN feedback signatures have been mainly sought for in OH, OH+, H2O, and H20+ absorption line profiles with Herschel. Similar queries with the high-J CO emission lines have not been performed even though they are feasible. We propose to look for feedback effects in high-J CO lines in 6 local AGN that are unique for this purpose. They have highly turbulent motions of warm H2 gas, as seen with Spitzer (Dasyra & Combes 2011). Their H2 lines are both very broad and strong, with typical velocity dispersions of 200-300km/s and M_H2/LIR ratios 5-160 times higher than that of Mrk231. In 4C12.50, the H2 line wings indicate the presence of a massive (5*10^7M_sun) outflow. If the strong H2 emission originates from gas shocked by AGN feedback mechanisms, it can be associated with strong high-J CO emission. Our sources allow for a direct comparison not done before: that of the gas velocity dispersion as probed by the two most abundant molecules, H2 and CO, in the T range where this becomes possible. We will also: (i) compare the widths of high and low J CO lines, (ii) locate the emission peak of the warm gas, (iii) model its excitation mechanism, and (iv) query for outflow-related line wings. Upon success, we will compute the warm gas mass (fraction) that the outflow entrains. The flow rate will be compared with the star-formation rate to indicate if the outflow is AGN driven, and if it can quench star formation. To achieve our goals we propose to observe with PACS the CO (15-14) and (18-17) lines in all 6 AGN, complementing them with PACS data of the [CII], [OI] 63 and 146 micron lines, and SPIRE spectra, when not available. The time investment for this basic experiment is modest, 11.6 hours with PACS and 5.8 hours with SPIRE.

Lead Scientist: Kalliopi Dasyra

Allocated time: 17.4 hours

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Hidden Dust in the Core-Collapse Supernova Remnant E0102

We propose to map emission from cold (<30 K), newly-formed dust in the ejecta of the core-collapse supernova remnant 1E 0102.2-7219 (E 0102) using Herschel PACS observations. E 0102 is a key object for understanding supernova dust production: it is one of few remnants where we have clear evidence of dust formation from mid-IR observations of ~10^-3 solar masses of hot dust in the reverse shocked ejecta. A large fraction of the newly-formed dust, however, may be located in the central, unshocked ejecta and its cold temperatures have kept it hidden at mid-IR wavelengths thus far. Observations with PACS at 70, 100 and 160 microns have the sensitivity and angular resolution to measure the mass of dust in the unshocked ejecta of E 0102 for the first time. With the observations proposed here, we will either discover a reservoir of cold dust in E 0102 or provide a direct counter-example to recent theoretical and observational studies that suggest supernovae are important sources of ISM dust.

Lead Scientist: Karin Sandstrom

Allocated time: 9.8 hours

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[CII] Observations of the Unexplored Atomic Gas-Rich ISM in Nearby Galaxies

We propose deep [CII] mapping of atomic-gas dominated regions in several nearby galaxies. These regions represent interstellar medium conditions that have not yet been explored with Herschel or any other facility and will remain unexplored in the foreseeable future if they are not observed with Herschel in OT2. We will use the proposed [CII] observations to measure the ISM heating rate and constrain the heat source in regions where the photoelectric effect driven by ultraviolet photons from young stars does not dominate. These observations are crucial for characterizing the low surface brightness [CII] emission, which is potentially an important contributor to the total [CII] emission from galaxies.

Lead Scientist: Karin Sandstrom

Allocated time: 34.7 hours

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Stellar dynamics ISM physics and star-formation in disk galaxies

We propose to observe 40 low-inclination, late-type spiral galaxies from our DiskMass Survey in all six Herschel PACS+SPIRE bands, requiring an allocation of 40.8 hours. The powerful combination of these Herschel data and our existing DiskMass data will allow us to calculate spatially resolved dust-mass and dust-temperature maps using both traditional SED fitting and more advanced radiative transfer modeling through a clumpy (fractal) medium. We will also be able to estimate bolometric corrections to dynamically measured stellar mass-to-light ratios made in the UV and optical; this will provide an unprecedented calibration of stellar-population-synthesis modeling at these wavelengths, which is important for applications at intermediate and high redshift. Finally, we will provide a novel comparison of spatially resolved dust properties with direct measurements of the stellar, atomic-gas, and dark-matter mass densities. We emphasize that, unlike other Herschel Key and GT programs, we use stellar kinematic data (collected over six years using 4m-class optical telescopes) to directly measure the mass surface density of each galaxy disk. Using these measurements of the disk potential and the proposed Herschel observations, our sample will be uniquely qualified to describe the detailed pressure balance in the interstellar medium and its correlation with the measured dust properties, as well as their empirical links to star formation and disk stability. These topics address our core understanding of the evolution and self-regulation of galaxy disks.

 

Lead Scientist: Kyle Westfall

Allocated time: 40.8 hours

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Balancing the Energy Budget in LIRGs: Towards a Complete PACS Spectroscopic Survey of Luminous Infrared Galaxies in GOALS

Luminous Infrared Galaxies (LIRGs; having LIR > 10^11 Lsun), emit a significant fraction of their bolometric luminosity in the far-infrared and are a mixture of single galaxies, interacting systems and mergers, exhibiting enhanced star formation rates and a higher fraction of Active Galactic Nuclei (AGN) compared to less luminous galaxies. With the Great Observatories All-sky LIRG Survey (GOALS), we are measuring the properties of a large, complete sample of 202 low-redshift LIRGs across the electromagnetic spectrum using Herschel, Spitzer, HST, Chandra, GALEX and a suite of ground-based observatories. As part of an accepted OT1 proposal, we are targeting the entire GOALS sample in the [CII] 157.7 and [OI] 63.2 micron emission lines and the OH 79 micron absorption feature, along with half the sample in the [OIII] 88 micron emission line. Here, we propose to complete our [OIII] emission line survey, and observe the brightest GOALS sources in the important [NII] 122 micron line with PACS. We will target 123 galaxies in [OIII] and 122 galaxies in [NII] line for a total requested time of 69.8 hrs. The PACS data will allow us to penetrate the dust and measure the spatial distribution, dynamics and overall energy budgets in a large sample of LIRGs at low redshift for the first time. In addition to providing a measure of the physical conditions in the warm, neutral and ionized ISM in LIRGs, the complete dataset will allow us to establish a precise, quantitative FIR-based measure of the star formation rate that can be used across a wide range of galactic luminosities, even in the presence of powerful AGN. GOALS, with its rich ancillary dataset that covers X-ray through millimeter wavelengths, provides the perfect sample for this study. Our proposed Herschel/PACS observations will greatly extend the work started with ISO, and lay the foundation for high-redshift extra-galactic studies with future facilities that will target the FIR and sub-mm spectral regions over the next decade.

Lead Scientist: Lee Armus

Allocated time: 69.8 hours

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The ISM Content of Type 2 Quasars: Testing Models of Black Hole Growth

The coevolution of central black holes and their host galaxies appears to be driven by starburst and AGN activity, and their respective energy feedback. Depending on the evolutionary state of the system, the AGN can be heavily obscured and appear as a Type 2 source. The relationship between the AGN and the galaxy has been extensively investigated by focusing on the stellar component of the host, especially the velocity dispersion and luminosity of the bulge, which empirically are closely coupled to the black hole mass. However, an insufficient amount of attention has been devoted to characterizing the ISM of the host galaxy. Here we propose to obtain FIR photometry with PACS and SPIRE for a volume-limited sample of Type 2 QSOs, complementary in redshift and luminosity to a sample of z < 0.5 Type 1 QSOs being studied by our team in OT1. Our goal is to derive robust dust masses and temperatures, and star formation rates for these two classes of QSOs, to test their physical connection. If, as has been suggested, Type 2 QSOs are the progenitors of Type 1 sources, we expect the Type 2s to be more gas (dust) rich, and perhaps have higher star formation rates, than the Type 1s. For objects at the mean redshift of z = 0.2, we can constrain the mass of warm (~60 K) and cold (~25 K) dust down to 3E+5 and 3E+7 solar masses, respectively, similar to levels found in the Milky Way. These data will provide a fundamental dataset for testing the evolutionary link between Type 1 and Type 2 QSOs, and the broader relationship between black hole growth and galaxy formation. The goals of this proposal mesh well with one of Herschel's main mission statements: "Unveiling hidden details of star and galaxy formation and evolution."

Lead Scientist: Luis Ho

Allocated time: 42.9 hours

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Extreme star formation in low-metallicity dusty blue compact dwarf starbursts

We propose to use Herschel/PACS+SPIRE to study dusty extreme star formation (SF) in a unique carefully-selected sample of 23 nearby low-metallicity dusty blue compact dwarf (BCD) galaxies in the local universe. Like extreme starbursts, and unlike most BCDs and other dwarf galaxies, their SF occurs in compact, dense regions with high star-formation rate (SFR) surface density. They are the best local analogs to study how stars form at high redshift, and complement the vast majority of more quiescent BCDs already observed by Herschel. Our BCD sample is unique among dwarf samples in that it has been constructed by choosing objects from the Sloan Survey with large MIR IRAS fluxes, similar to the 2 active BCDs that have been recently discovered by WISE through their very red WISE colors. It also has all the ancillary optical, near-infrared, and Spitzer data, necessary for a detailed interpretation of the Herschel data. With PACS+SPIRE photometry, we will fit the spectral energy distributions (SEDs) constrain the mass of the cool dust component -- hence better estimate the total dust mass -- and compare it with the stellar and gas masses. We will also look for trends in SED shape with compactness and SFR. By combining the data on active BCDs with that on passive BCDs in the Spitzer and Herschel archives, we will be able to compare SEDs and modes of SF over a wide range of SFRs, metallicities, and dust properties. Ultimately, these extreme BCD starbursts may provide local templates to compare with the dusty galaxies in the high-z universe.

Lead Scientist: Leslie Hunt

Allocated time: 16.3 hours

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Seeking Obscured Starbursts of High Luminosity with PACS Measures of [CII]

PACS observations of the [CII] 158 micron emission line are proposed for 56 luminous, dusty galaxies to determine if there are starbursts so obscured by dust that the starbursts are weak or invisible in the mid-infrared PAH features observed with the Spitzer Infrared Spectrograph (IRS). Are there LIRGs and ULIRGs classified as AGN which really are heavily obscured starbursts? Because of the much smaller extinction affecting the [CII] feature, large f([CII])/f(PAH) ratios would show the presence of such obscured starbursts. Sources proposed include 18 "pure" starbursts to improve the f([CII])/f(PAH) calibration for these, 32 sources classified as AGN/starburst composites, and 6 sources with weak PAH and very strong silicate absorption. This proposal builds on the success of our OT1 program for which a summary is given of the excellent [CII] detections so far obtained and analyzed for a variety of luminous sources with IRS starburst/AGN classifications.

Lead Scientist: Lusine Sargsyan

Allocated time: 9 hours

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Investigate the Physical Nature of An Extraordinarily Far-IR bright Galaxy Discovered by WISE

We request a total of 5.3 hours of Herschel PACS and SPIRE time to investigate the physical nature of an extraordinarily far-IR bright system discovered by the WISE data. This object was first selected to have an extremely red mid-IR SED, very bright at 22micron (38mJy) and not detected at WISE 3.4 and 4.5 micron. At the WISE 12micron position, we found it has IRAS far-IR emission, (600+-59)mJy & (855+-170)mJy at 60 and 100 micron respectively (2' beam). A small 350 micron map, taken with the CSO SHARCII under an exceptionally good weather condition, has detected a 32mJy source at the WISE position. The large discrepancy between fluxes at IRAS 100 micron and CSO 350 micron is intriguing. We propose to clarify the nature of this system --- whether a single or a group of far-IR bright sources --- by utilizing Herschel's high spatial resolution and fast mapping speed. The Herschel photometry, together with the Keck spectra, will allow us to determine the full IR SEDs and the physical parameters such as IR luminositie, SFR and star formation efficiecy.

In addition, the deep Keck LRIS spectrum of the galaxy closest to the WISE 12 micron position has found an emission line object at redshift of 0.593, and the Keck NIRC2 K-band Adaptive Optics image shows an extended, disk like galaxy. At z=0.593, the strong IRAS far-IR emission implies very high L(FIR), in the range of (2.1-10)e+12Lsun, with the lower limit set by considering only 1/4 of the IRAS fluxes. We propose to obtain SPIRE FTS spectroscopy to measure [CII]158um line. At this redshift, this line can only be observed by Herschel, and is outside the ALMA wavelength window. With the measured [CII]-to-L(FIR) ratio, we can constraint the molecular gas mass of Source A by utilizing the correlation between [CII]-to-L(FIR) and L(FIR)/M(H2). Even with null detection, our observation will provide meaningful constraint on the ISM properties of this ULIRG.

Lead Scientist: Lin Yan

Allocated time: 5.3 hours

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Probing Physical State of ISM in IR Bright QSOs Discovered by WISE and SDSS

Combining WISE and Sloan Digital Sky Survey (SDSS), we have identified a sample of 9 QSOs with flux(22um)>100mJy and with spectroscopic z~0.1−0.2 for Herscel PACS spectroscopy. Our targets are so bright at 22 micron, even without far-IR observations, their predicted fluxes at 100 micron would exceed 300 mJy based on the type-I QSO SED which has the minimum far-IR emission. For this bright QSO sample, we request a total of 23.8 hours to measure far−IR fine structure lines with PACS spectrometer. The extremely bright IR fluxes and the narrow redshift slice allow us to simultaneously observe the two brightest far−IR lines, [OI]63um and [CII]158um. We can therefore estimate the line ratios, in combination with Photo−Dissociation Region (PDR) models, to provide physical characterization, including gas temperature, density and intensity of UV radiation field, of the warm interstellar medium (ISM) in these luminous objects. The proposed observations will allow us to determine [CII] line and far-IR continuum luminosities. With the [CII]-to-L(FIR) alone, we can already estimate L(FIR)/M(H2) ratio utilizing the published correlation by Gracia-Carpio et al. 2011, thus allowing estimates of molecular gas masses. The far−IR continuum estimates, with the four mid−IR photometry from WISE, can determine if the total IR luminosities could be produced by starbursts, and if so, give estimates of star formation rates. One additional advantage of this sample is that their high SNR SDSS spectra can be used to calculate black hole masses based on fairly reliable low ionization lines. The calculation will allow us to investigat e any relation between black hole properties, including mass and accretion rate, and the gas medium probed by the far−IR data. These proposed spectra will contribute to building up a Herschel legacy with far−IR spectroscopy dataset which will extend beyond ALMA and JWST.

Lead Scientist: Lin Yan

Allocated time: 23.8 hours

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Dust Emission and Star Forming Activity in the High Redshift Weak Line Quasars Gas and Star Formation in IC1613

We propose to carry out PACS and SPIRE mapping of the dust continuum emission from the nearby, low metallicity dwarf galaxy IC1613. The maps will have spatial resolutions of 24 pc to 120 pc, allowing us to probe dust temperatures, formation and destruction processes on the scale of individual star-forming clouds. The results will also be combined with our extensive ancillary datasets to search for evidence of molecular hydrogen. IC1613 fills an important niche in the archive, as Herschel's resolution and sensitivity enable us to push these kinds of studies to lower metallicities and lower star formation rates than have previously been accessible.

Lead Scientist: Lisa Young

Allocated time: 22.5 hours

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A Herschel/PACS mapping of far-infrared emission lines from the nuclear spiral in M31

The nuclear spiral in M31, consisting of ionized and neutral dusty gas clouds, shows optical emission lines characteristic of LINERs. Yet the lack of UV radiation from either an active nucleus or massive young stars makes the ionizing source of this nearest LINER a longstanding puzzle. We propose a PACS spectroscopic mapping of several fine structure lines, including [C II], [O I] and [O III],from the nuclear spiral. We will derive for the first time the spatial distribution and kinematics of the circumnuclear neutral gas in M31, with an unparalleled linear resolution of 40 parsec for a massive external galaxy. These FIR lines, together with the optical and mid-IR emission lines mapped by HST and Spitzer observations, will enable us to assess the importance of various ionization/excitation mechanisms. Specifically, we will test the cosmic-ray heating scenario, which is favored by energetics considerations for the nuclear spiral. This study will advance our understanding of the physical regulation of galactic circumnuclear environments, which is in turn crucial to understanding the evolution of super-massive black holes and their host galaxies.

Lead Scientist: Li Zhiyuan

Allocated time: 9.9 hours

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Searching for a missing molecular mass through dust emission in the huge HI collisional ring of NGC 5291.

We propose PACS+SPIRE observations from 70 to 500 micron of the giant (180 kpc across), massive (~5.5 10^10 Msun of HI), strongly star-forming collisional ring around NGC5291, a unique gas-rich object in the nearby Universe. These observations, in combination with available data and models, will allow us to not only study star formation and the dust properties in an unusual and extreme environment, but also to get insight into the nature of Dark Matter. Indeed our team showed that the gravitationally bound objects formed within the ring of NGC5291 contain an unexpected dark component. It is thought that this matter should be baryonic as the material in the collisional ring comes from galactic disks. The most likely candidate is H_2 that is not properly traced by CO. Herschel will allow us to trace this unseen component through dust emission and constrain its nature. The method requires to characterize the dust properties and estimate the dust/gas mass ratio, which are not known in collisional rings and might differ from those in other environments. Indeed, collisional rings are created by high speed collisions. The strong shocks generated by the impact have likely affected the dust properties. Through state-of-the-art modeling of the SED from the UV to the radio, we will constrain the properties of the dust such as their temperature, the distribution of the grain sizes, etc. Addressing the question of dust processing in high-speed collisions is fundamental to derive the molecular gas mass. Finally having an accurate estimate of the total molecular mass, we will be able to address star formation laws, in particular the Schmidt-Kennicutt relation which is suspected not to be universal. This will allow us to determine whether it varies with the environment, having selected an "extreme" one, such as the collisional ring of NGC5291. The project will require the combination of already available VLA HI observations, star formation tracers and Herschel PACS+SPIRE photometry.

Lead Scientist: Mederic Boquien

Allocated time: 2.2 hours

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High resolution observations of the warm dust in M33

We request 9.9 hours of observing time to map M33 at 70 micron. This project will enable a spatially-resolved investigation of HII regions in this galaxy, with the goal of determining changes 1) in the respective amount of PAH, stochastic and equilibrium dust emissions, in order to 2) constrain the radiation field and the properties of dust emission as a function of the evolutionary phase of the HII regions and across the disk of the galaxy. We will resolve the internal structure and physical properties of the HII regions down to ~24 pc (<6"), and construct spatially-resolved, pixel-based, UV-to-FIR SEDs. This proposal is a key complement to the HerM33es key project which mainly focuses on the mapping of major FIR cooling lines, with only a small fraction of the time dedicated to imaging from 100 micron to 500 micron (PACS and SPIRE).

Lead Scientist: Mederic Boquien

Allocated time: 9.9 hours

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PaLARS -- PACS spectrsocopy of the Lyman-alpha Reference Sample

In observational studies of the high-redshift universe, the potential of the HI Lyman-alpha (Lya) to answer open cosmological questions is well established. This potential, however, is hampered by the fact that Lya is a resonant line, scatters in HI, and undergoes a complicated radiative transport. It has recently been suggested that certain structural geometries of the multiphase ISM could be even more important than the overall dust content in regulating the Lya visibility. The simplest scenario to unify the requirements for Lya with what we know about the phases of the ISM in galaxies is that these scattering surfaces must be the typical photodissociation regions (PDR), surrounding dusty molecular clouds within.

Currently there is no observational test of this theory. We propose here to obtain unresolved PACS spectroscopy of the [C II] and [O I] lines, and photometric observations in all three channels, of 10 galaxies in the local LARS (Lyman Alpha Reference Sample) sample. These data will allow us to 1) Measure the total mass of PDR gas and contrast it against the total HI mass (already obtained). We will test the hypothesis that when more of the HI is condensed around high-density clumps, the ISM is more conducive to the transmission of Lya photons. 2) We will use the [O I]/[C II] ratio and the total ratio of ([O I]+[C II])/FIR in conjunction with PDR modelling, to constrain the HI density in PDRs. 3) From the PACS photometric points we will model the IR SED, compute dust masses, gas-to-dust ratios, attenuation from UV/FIR, and contrast them all against Lya properties.

Lead Scientist: Matthew Hayes

Allocated time: 12.1 hours

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Dust in the HIghMass Galaxies

We propose to obtain the PACS and SPIRE scan maps of a sample of 34 exceptionally gas-rich galaxies extracted from the ALFALFA extragalactic HI survey. These very HIgh HI mass (HIghMass) galaxies have HI masses > 10^10 Msun and are also very gas-rich for their stellar masses; 17/34 have M_HI>M_star. Are they in an arrested stage of evolution or do their huge HI disks, evident in our HI synthesis maps, result from recent baryon accretion? In combination with the HI synthesis maps (EVLA, GMRT, WSRT), GALEX UV, Halpha, optical broadband and CO studies, FIR/submm maps will cover a critical wavelength range of the dust emission spectral energy distribution and will allow us to determine the dust masses, temperatures and grain size distributions so that we can explore the interplay between the dust, stellar, gas and dark matter components within each galaxy and identify the dust variation trends within the HIghMass sample. In particular, Herschel observations will help us to (1) explore the unique dust behavior in the HIghMass galaxies and map the extent of the cold dust disk; (2) test the origin and evolutionary stage of them and infer molecular masses via the dust to gas ratio; (3) probe the dust-obscured star formation and study the dust heating mechanisms in their extended massive HI disks. Identified first as a class only by ALFALFA, the HIghMass galaxies represent the local counterparts of the populations which are likely to dominate future studies of HI at higher redshift with the Square Kilometer Array.

Lead Scientist: Martha Haynes

Allocated time: 20 hours

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The Nature of Star-formation in Halos: HI Bridges and Streams in the MW and the M81/M82 group

We have now reached a relatively mature understanding of the physical processes that regulate the ISM in galaxies, but we are woefully ignorant of the details of the cycles between gas in and outside of galaxies. This is unfortunate because understanding the gas physics in a wide variety of environments is the key to determining the relevance of the physical mechanisms that have been invoked for driving galaxy evolution -- from the feeding of star formation through accretion of cold gas to the regulation of star formation through the mechanical energy ejected by massive stars and AGN. To help to overcome our ignorance about the nature of star formation in different environments, in this case in galaxy halos, we propose to use PACS to observe [CII] in many selected regions of the "bridges" of HI in the nearby group of M81 and in the Magellanic stream, two of the nearest intergalactic gas flows. These regions are excellent targets for this type of study because it has a wide range of HI column densities and stars have recently formed in the gas flow between its galaxies. In response to the comments of the OT1 panel, the Magellanic stream was added as a foil to the M81 group in that it has scant evidence for recent star formation. [CII] is the main coolant and an excellent tracer of the cold neutral medium in galaxies. By combining these data with dust maps from Spitzer, Herschel, HI and H-alpha observations, we will investigate the mass balance between the warm and cold neutral medium to constrain the role of turbulence in regulating this balance, which is key to the cooling and fragmentation of gas and to regulating star formation. Investigating the nature of star formation in a halo of a galaxy or group is one of the critical first steps in understanding what occurs during the cosmological accretion of gas and thus help determine what processes drive the evolution of the ensemble of galaxies.

Lead Scientist: Matthew Lehnert

Allocated time: 26.9 hours

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Nearby Universe Herschel observations to unveil the role of dust in long gamma-ray burst host galaxies

Long gamma-ray bursts (LGRBs), are the brightest transient events in the Universe. This, combined with their wide range in redshift and the fact that they are associated with the collapse of massive, low metallicity stars, establishes LGRBs as powerful probes of star formation and an unbiased method for identifying high redshift galaxies. Targeted observations of LGRB hosts have shown them to be typically blue, low metallicity, dwarf to intermediate mass galaxies. However, the role of dust in the star formation history, chemical enrichment and evolution of these sources is currently still unclear, yet its importance cannot be overstated as it is directly related to the origin of the LGRB. The dust properties of LGRB host galaxies can be uniquely investigated with Herschel due to its ability to probe the peak of the dust emission, particularly in the nearby Universe where we can gain a fundamental understanding of the role of dust in these systems. In this proposal we request 48 min of Herschel (PACS and SPIRE) observations of 2 local z≤0.1 LGRB host galaxies, already well studied over a large part of the electromagnetic spectrum. Our proposed targets are the only Herschel-detectable LGRBs hosts in the local Universe which have properties resembling those of the general LGRB population, setting our study key in understanding the processes and interstellar medium (ISM) conditions associated with LGRBs. Our proposed observations will enable us to examine in detail currently unconstrained properties, such as the dust mass, dust temperature, dust to gas ratio, star-formation history and extinction. In addition, for the first time, we will be able to link the LGRB explosion to the conditions and chemical evolution of the ISM as as well as examine the role of dust in LGRB hosts harbouring metal poor, massive stars.

Lead Scientist: Myrto Symeonidis

Allocated time: 0.8 hours

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Can AGN keep the gas in their host galaxies from becoming gravitationally bound and forming stars?

The discovery of molecular outflows from AGN and starburst galaxies has been a major success of the Herschel Space Observatory and moved AGN feedback into the focus of Herschel science. However, feedback is more than winds, and observations of winds alone will only provide a limited picture of how AGN regulate star formation in galaxies. Recent observations suggest that gas-rich AGN host galaxies can have very low star-formation rates, up to 60 times less than expected for their gas surface densities. Why are these galaxies not forming stars? One possibility is that the injection of mechanical energy through the AGN is making the gas too turbulent to become gravitationally bound, to collapse and to form stars. Thus, star formation in AGN host galaxies may be regulated by fundamentally similar mechanisms as star formation in molecular clouds in the Milky Way and other 'ordinary' galaxies.

Here we propose to measure [CII]158 with PACS in 6 nearby galaxies with radio nuclei to test this hypothesis. We focus on galaxies with radio nuclei without strong star formation or quasar emission, because we wish to study the consequences of the rapid injection of mechanical energy through the AGN into the ISM. Radio-dominated AGN provide the cleanest environment for such a study because their UV radiation is faint, and we expect the shock contribution to dominate over that of UV heated star forming gas. However, many of our results can be cautiously extended to all types of mechanical interactions between AGN and gas. We will compare the [CII] line fluxes with those of warm H2 in the Spitzer archive. For highly turbulent gas that is not gravitationally bound, we expect the gas not to be well shielded, resulting in high [CII]/H2 ratios of 1-5. For the same reason, [CII] could also be an interesting tracer of low surface-brightness emission from winds. NIR imaging spectroscopy will serve as a benchmark to separate systemic line emission from putative wind components and to measure turbulent velocities in the CNM.

Lead Scientist: Nicole P. H. Nesvadba

Allocated time: 5 hours

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Feedback from luminous obscured quasars

Quasar feedback has become a major ingredient in galaxy formation models, invoked to explain the absence of overly massive galaxies, the hot intracluster medium and the black hole / host galaxy correlations. Using ground-based spectroscopic observations, we have discovered high-velocity ionized gas outflows from luminous obscured quasars, which could be the long-sought ``smoking-gun" signature of quasar feedback. We propose deep photometric observations with Herschel to determine the far-infrared spectral energy distribution of these objects. We will use these data to confirm that the observed outflows are driven by the supermassive black hole activity rather than by star formation in the host galaxy. Furthermore, we will quantify the relation between the kinetic energy of the outflow and the radiative power of the quasar. Herschel observations are the only avenue to establish the driving mechanism and energetics of quasar feedback.

Lead Scientist: Nadia Zakamska

Allocated time: 5.8 hours

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Foreground emission (diffuse and point-sources) in two high Galactic latitude regions of the EBEX and BICEP experiments

We propose to study the far-IR/submm emission (both sources and diffuse) of two southern regions around declination -50 and -57 degrees which have been and will be surveyed by the Cosmic Microwave Background (CMB) experiments Background Imaging of Cosmic Extragalactic Polarization (BICEP and BICEP2) (Chiang et al., 2010) and `E and B Experiment' (EBEX) (Reichborn-Kjennerud et al., 2010). Our goal is to measure and characterize the Galactic diffuse and point source emissions which represent the main contaminants to the CMB in the frequency range covered by Herschel, which is complementary to the one of the above CMB experiments, "directly in the area which will be covered by those experiments". These measurements will bring invaluable information to control the foreground emissions in those experiments, therefore contributing to gain insight into most important cosmological processes related to the CMB anisotropies, which compete with the diffuse Galactic and extra-Galactic point source emissions.

Lead Scientist: Paola Andreani

Allocated time: 18.7 hours

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Shock-excited Galaxies in the Green Valley in Compact Groups: Clues to Morphology Evolution in Dense Environments

Compact groups of galaxies represent density enhancements in the Universe comparable with clusters and are dominated by early type galaxies that lie in the "Green Valley" between the blue and red sequence. Our observations of a sample of such groups has revealed that 10 percent of our targeted group members show unusually powerful mid-IR H2 emission lines relative to PAH emission--suggesting shock-excitation. Most of these galaxies lie in the optical green valley, and exhibit specific star formation rates that lie between spirals and elliptical suggesting that they are a transition population in which shocks may play a role in their color evolution.

We propose to map key far-IR cooling lines [OI], [CII] and CO with the PACS and SPIRE spectrometers to both map and quantify the strength and distribution of shocks to search for clues about how they might be affected by their environment. We will also use PACS and SPIRE imaging to constrain dust SEDs to estimate SFRs and dust/gas masses to explore whether the shocks may heat the gas above the threshold for star formation--hence shutting down new star formation. Alternatively, by comparison with VLA HI maps which show considerable tidal material in the groups, we will search for evidence that accretion from tidal streams is responsible for re-igniting new star formation-thus modifying their optical colors. This proposal will, for the first time, test whether shocks may play a transformative role in galaxy evolution.

Lead Scientist: Philip Appleton

Allocated time: 50 hours

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The Most Luminous Obscured Galaxies and Quasars Revealed by WISE and Herschel

NASA's Wide-field Infrared Survey Explorer (WISE) has surveyed the entire sky at 3.4, 4.6, 12 and 22 microns (W1, W2, W3, and W4), reaching sensitivities hundreds of times deeper than IRAS. We have used WISE photometry to select an all-sky sample of objects which are extremely luminous. The objects are prominent in W4, but faint or undetected in W1 and W2 (W12drops). Followup spectroscopy of ~ 100 sources shows over 70% of W12drops have redshifts > 1.6, which with OT1 PACS and SPIRE photometry of 27 sources leads to over 1E13 solar luminosities, with ~ 10% exceeding 1E14 solar luminosities. High resolution adaptive optics imaging shows these objects are unlensed. We request 47.3 hours of Herschel time to complete the all-sky sample of the brightest 185 W12 drops, fulfilling the primary WISE objective of finding the most extreme luminous IR galaxies in the Universe. These superlative objects will be the most fruitful for detailed studies of the physics of star formation, AGN fueling, and feedback in the most active galaxies.

Lead Scientist: Peter Eisenhardt

Allocated time: 47.3 hours

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A high-resolution look at dust emission from shocks and star-forming regions in Stephan's Quintet

Stephan's Quintet (SQ) is a compact group of galaxies, where tidal interactions have brought large amounts of gas into the intergalactic medium (IGM). Spitzer IRS observations revealed an unusually bright H2 line emission from a giant (40 kpc long), X-ray emitting shock attributed to a high-speed (1000 km/s) galaxy collision. The extreme H2-to-PAH flux ratio (1000 times more than star-forming galaxies) suggest that H2 is predominantly excited by shocks rather than UV heating from star-forming regions. From our OT1 P2 project, we recently obtained SPIRE images of SQ, revealing for the first time the cold dust associated with the warm H2 gas in the shock. However, the large SPIRE beams do not separate star-forming regions from shocked gas. To confirm what fraction of the dust emission comes from the shock, we propose PACS observations with higher angular resolution. These observations are further motivated by our recent PdBI CO(1-0) observations, which break the SQ shock in large complexes (3-5 kpc in size) with a range of line widths (40-200km/s). Some of them could be sites of star formation. PACS is the only instrument providing the sensitivity and angular resolution to quantify star formation on these scales. With the proposed observations, for the first time for IGM gas, we will be able to (1) calibrate the CO to H2 conversion factor using dust emission and estimate the total cold gas content of the CO complexes, (2) study the impact of turbulence on star-formation efficiency, and (3) constrain the dust size distribution. The results will have important consequences on our understanding of the energetics and the role of dust in cooling the IGM gas in high-redshift mergers, and in the formation of galaxies.

Lead Scientist: Pierre Guillard

Allocated time: 13.1 hours

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PACS on the cap: probing the dissipation of kinetic energy in the M82 superwind

Starburst-driven outflows -superwinds- are ubiquitous in galaxies with intense star-formation and are a complex phenomenon, literally requiring observations at every wavelength to unravel their energetics, outflow rates, and cosmological significance. We propose here, as part of a comprehensive study to understand the entrainment of material in winds, [OI] and [CII] spectroscopy with PACS of the "cap" in M82. The cap is a region of emission well out of the plane of M82 and provides the most robust evidence that winds escape. But this may not be true. Only through an understanding the how entrainment cools the wind material can we say this with any surety. That requires understanding how the wind energy is dissipated in entrained material like the cap. The proposed PACS observations follow our recent and puzzling detections of bright H2 rotational and [SiII] line emission with Spitzer IRS in the cap, as well as a non-detection of CO(1-0) and (2-1) in deep spectroscopy with the IRAM 30m telescope. The far-IR [OI] and [CII] lines will uniquely probe the relative contributions of the shock vs. photo-ionization in the cap. The cap offers a particularly clean environment to model the wind-cloud interaction. The results will be a critical test of a detailed physical model we are developing to describe the dissipation of kinetic energy in multiphase winds. This is a crucial step in understanding less detailed, high-redshift observations of superwinds, as well as the importance of winds for the evolution of galaxies and the inter-galactic medium.

Lead Scientist: Pierre Guillard

Allocated time: 11 hours

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Energetics of AGN feedback: [CII] line cooling in radio-galaxies with jet-driven outflows

Observations of ionized and massive neutral gas (HI) outflows in radio-galaxies (RGs) suggest that radio-jet feedback has a galaxy-scale impact on the host interstellar medium (ISM). Our recent results from Spitzer IRS spectroscopy of a small sample of 8 HI-outflow RGs show that all of them have bright H2 line emission that cannot be accounted for by UV or X-ray heating, and that the H2 gas is extremely turbulent, with H2 S(1) line FWHM = 450-720 km/s. We suspect that the radio-jet is injecting large amount of turbulent kinetic energy into the ISM, but little is know about the role of the turbulence in forming cold neutral gas from warm gas, and in regulating star formation. Our calculations and shock modeling predict that in turbulence-dominated gas, this line could be brighter than the H2 S(1) line. We propose PACS [CII] spectroscopy to test this, and probe an important missing piece of the ISM line cooling. These sources span a large range of IR luminosities and jet kinetic power, and provide ``clean'' environments where jet-induced shocks and turbulence seem to govern the physical state of the gas. This will uniquely complement our accepted (OT1, P1, not scheduled yet) PACS [OI] and SPIRE spectroscopy on these sources, allowing us to estimate the relative contributions of the shock vs. photo-ionization. Such a detailed understanding of the energetics of radio-jet feedback is crucial to interpret high-redshift observations and input numerical models of galaxy evolution.

Lead Scientist: Pierre Guillard

Allocated time: 17.6 hours

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Water Legacy of HIFI -- Observing the richest water

The archetypal ultraluminous infrared galaxy Arp 220 revealed a remarkably rich spectrum in Herschel SPIRE FTS observations, including luminous emission from warm CO and water. The spectrum also revealed the presence of a massive molecular outflow, traced by P Cygni line profiles in the molecular ions OH+ and H2O+, and possibly H2O. Comparison of the column densities of these ions relative to water (and the absence of the ion H3O+) indicated that only an XDR powered by an X-ray-luminous AGN is capable of explaining the relative abundances; that these molecular ions are the same species that are participating in the outflow suggests there may be a connection between the AGN and the outflow.

Because the FTS did not resolve the lines, only limited information regarding the outflow and the column densities could be derived from the saturated lines. To much more accurately characterize both the physical and chemical state of the gas (in particular the water chemistry) and the mass and energetics of the outflow, we propose to obtain HIFI observations of a number of H2O, H2O+, and OH+ emission and absorption lines (including those exhibiting P Cygni profiles). In addition, we propose to observe two fairly strong unidentified emission lines, which fall quite close to the expected frequencies of the HCN and HCO+ J=6-5 rotation lines. Lower-lying transitions of both species have been measured from the ground; the apparent velocity offsets from the expected positions may be the consequence of complex emission and/or absorption profiles. In the case of HCN, the FTS data have established that the J=13-12 line and above are seen in absorption.

Lead Scientist: Philip Maloney

Allocated time: 27 hours

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Toward the Mass and Origin of Dust in Early-Type Galaxies

The origin and evolution of the dust in early-type galaxies are two of the key questions to understanding their evolution at late times. The two main scenarios to produce their dust are in situ formation from the winds of cool giants and the accretion of small, gas-rich satellite galaxies. The later scenario appears to be the only viable explanation for the several orders of magnitude variation in the amount of dust at fixed stellar mass, as in situ formation implies that the dust content should approximately scale linearly with stellar mass. Yet our demographic studies of a well-selected sample of early-types show that dust is present in roughly half of them, which implies a very high merger rate given the expected short lifetime of dust in their hot ISM. We propose SPIRE photometry of 11 of the 45 early-type galaxies in our previous Spitzer and HST studies. These 11 galaxies have 3-channel MIPS photometry, HST images, and deep ground-based photometry and spectroscopy. There are 12 additional galaxies that meet these criteria and already have executed or planned observations. Our goal is to measure the cold dust masses for these galaxies and thus determine the likelihood that the dust originates from minor, gas-rich mergers. The SPIRE data are critical to accurately measure the dust masses in these galaxies as the vast majority are active and thus may have a substantial hot dust component that biases mass estimates from the existing, shorter-wavelength IR photometry. These data will be combined with archival SPIRE data for the remaining 12 galaxies with detections in our Spitzer study to measure the distribution of dust masses our representative sample of early-type galaxies and thereby better constrain the origin of the dust.

Lead Scientist: Paul Martini

Allocated time: 2.2 hours

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Diffuse Dust Emission from Black Hole-driven Outflows in Halo-centered Massive Elliptical Galaxies

Dust grains ejected into the hot interstellar gas in group-centered elliptical (E) galaxies are destroyed by ion-grain collisions, but during their short lifetime (10 Myrs) the grains emit sufficiently in the far infrared (FIR) to be easily observable. Remarkably, against this background emission, observations with Spitzer discovered many E galaxies with much stronger and spatially extended FIR emission from colder grains 5-10 kpc distant from the galaxy cores. Extended excess cold dust emission is interpreted as evidence of recent feedback-generated AGN energy outbursts in these galaxies, visible only in the FIR, from buoyant gaseous outflows from the galaxy cores. With Spitzer a quasi-radial plume of AGN-heated gas is resolved in only one galaxy, but marginally resolved in others. We request Herschel observations of a small sample of these E galaxies to confirm the existence of excess, spatially extended dust and to possibly spatially resolve more quasi-radial buoyant dusty gaseous plumes. Based on a detailed analysis of Spitzer data, our sample for Herschel is chosen to maximize the likelihood of discovering new FIR evidence of post-feedback events from massive galaxy-centered black holes.

Lead Scientist: Pasquale Temi

Allocated time: 26.4 hours

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Extreme PDRs: hard stellar radiation at low metallicity.

We propose to use the unique power ot Herschel to analyze the most extreme resolvable photdissociation regions, i.e. those at low metallicity and energized by hard radiation. With a modest investment of observing time, we will probe a unique part of parameter space, providing a strong lever arm to test the validity of PDR models. Furthermore, the conditions of low metallicity and hard field are exactly those which are more prevalent in the early universe compared to today, and increasingly important to understand the interstellar medium of early galaxies. The regions we propose to study in detail in the local universe are a unique window into how the first stars affected their environments, which we will not easily study at this resolution.

The only PDRs close enough to resolve their structure and at low metallicity are in the Magellanic Clouds. There are only a few nebulae in the Clouds that are clearly energized by the extremely hard radiation from Wolf-Rayet Stars, and we will analyze two in each galaxy, which combined with our existing Spitzer and Herschel data will provide unprecedented information on PDR physics throughout the universe.

Lead Scientist: remy indebetouw

Allocated time: 20.5 hours

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Characterising the ISM of bright lensed star-forming galaxies across cosmic time with the SPIRE FTS

We have shown that SPIRE is capable of exploring high-redshift galaxies spectroscopically, provided those galaxies are sufficiently bright.

Here, we propose to exploit its wide wavelength coverage to study the powerful diagnostic rest-frame FIR cooling lines from a sample of 48 bright, lensed - but intrinsically typical - submm galaxies (SMGs). Our targets span 1 < z < 3.1 and 11.5 < log L(FIR) < 13.5, and are selected from panoramic Herschel imaging surveys that are uniquely capable of providing a large, reliable sample at S(350um) > 200mJy, with excellent ancillary data.

We will detect or place sensitive limits on key atomic and ionic cooling lines, e.g. [C II], [O I], [O III], and combine these with ground-based observations of 12CO, 13CO, C I and dense-gas tracers to perform a detailed analysis of their ISM and thence understand their energetics and temporal evolution. Using these data we will:

1) empirically constrain the interplay between gas cooling and heating in IR galaxies, mapping the evolution of the star-formation efficiency, exploiting our large sample to separate dependencies on L(FIR) and z, and thereby establishing fundamental relationships for the IR galaxy population;

2) conclusively address the issue of the contribution of AGN to IR galaxies;

3) coadd spectra in the rest frame to delve up to sqrt(48)x deeper than an individual spectrum, to confirm/quantify the signature of powerful feedback via OH molecular outflows, and add powerful diagnostics, e.g. H2O, [O I] and high-J lines, allowing a complete characterisation of the entire FIR spectrum.

Goals 1 and 3 drive the requirement for a sample of 48 SMGs. All our goals require Herschel and cannot be addressed by other facilities.

We stress that the scientific legacy of ISO and Spitzer has in large part been based on the wealth of data in their spectroscopic archives and the same will likely be true for Herschel.

Lead Scientist: Rob Ivison

Allocated time: 94.1 hours

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Mass-metallicity relation of infrared-luminous galaxies assessed by extinction-free metallicity diagnostics

LIRGs and ULIRGs are found to deviate strongly from the mass-metallicity relation. More specifically, at a given stellar mass, the metallicity of LIRGs and ULIRGs, as inferred from optical spectroscopy, is much lower than the value expected from the mass-metallicity relation observed in normal star-forming galaxies. This "metallicity anomaly" of LIRGs and ULIRGs has been ascribed, by many models, to the inflow of metal poor gas, from the galaxy outskirts, induced by the tidal forces associated with these merging systems. However, an alternative possible scenario is that in these dusty systems optical spectra only probe the outer, metal poor regions, while the bulk of the gas is actually metal rich, but it is heavily absorbed by dust.

We propose a definitive test of the scenarios discussed above by obtaining an independent, extinction-free measurement of the gas metallicity in a sample of LIRGs-ULIRGs, by exploiting newly developed far-IR metallicity diagnostics. In particular, we have recently shown that by measuring the relative intensities of the fine structure lines [OIII]52um, [OIII]88um, [NIII]57um and [NII]122um, it is possible to constrain the gas metallicity with high accuracy and in a wavelength range nearly unaffected by dust extinction. If these far-IR diagnostics confirm the low metallicities observed in the optical spectra, this would support models envisaging inflow of metal poor gas in interacting systems. If, instead, the far-IR diagnostics measure much higher metallicities, this would favor the scenario where the bulk of the gas is metal rich, but heavily absorbed, and it has been elusive to optical observations.

Lead Scientist: Roberto Maiolino

Allocated time: 34.6 hours

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Herschel observations of the most distant known quasars

Understanding the formation and evolution of the first quasars, their supermassive black holes and host galaxies is one of the most important goals of both observational and theoretical astrophysics. In the last decade there has been immense progress in the discovery and study of z>6 quasars but since the discovery of SDSS J1148+5251 with z=6.42 by Fan et al(2003) almost a decade ago no quasar has been discovered with z>6.5. Recently, using data from the UKIDSS survey we have discovered a bright (K[Vega]=17.7) quasar ULAS J1120+0641 (Mortlock et al, 2011) which is the most distant quasar currently known at z=7.085, smashing the previous record of z=6.44 by a large margin. Furthermore, in the last few months, using data from the ESO VISTA public surveys, we have discovered three more quasars at z>6.5, with similar rest frame UV luminosity as ULAS J1120+0641 and redshifts of z=6.6, 6.8 and 6.9 respectively. Observations with the Plateu de Bure Interferometer of the z=7.085 quasar ULAS J1120+0641 have already revealed a significant detection of the [CII] 158micron cooling line which is the dominant interstellar medium (ISM) gas cooling line in star-forming galaxies confirming the presence of an ultraluminous star-forming galaxy associated with this quasar. In this proposal we shall carry out PACS and SPIRE photometry in the wavelength range 100-500microns corresponding to 12-60microns in the rest frame in this sample of four z>6.5 quasars with the goal of measuring the shape and luminosity of the FIR continuum in these primeval objects. These measurements will provide unique constaints on the star-formation rate, dust mass and dust temperature of the earliest massive star-forming galaxies.

Lead Scientist: Richard McMahon

Allocated time: 5.6 hours

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Heating the cool gas filaments in NGC 1275.

We propose PACS [CII], [OI] and [NII] spectra to determine the source of heating for the cool (20-300 K) gas in an isolated, quiescent gas filament in the Brightest Cluster Galaxy (BCG) NGC-1275, the brightest of all cluster cool-core galaxies. The heating mechanism of this cool gas in BCGs is not well understood, It is also crucial to understanding analogous "negative feedback" processes in star-forming galaxies at high redshift. In combination with our SPIRE spectroscopy, and other deep multi-wavelength measurements, the proposed observations will provide a unique data set that will allow us to develop a consistent physical picture of the processes that energize the filaments. NGC-1275 is the only cool-core BCG where we can separate the quiescent filaments from the nuclear region influenced by the AGN. This will allow us to directly compare the heating of cool gas in these filaments with that in the nuclear region.

Lead Scientist: Raymond Oonk

Allocated time: 3.8 hours

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Dust Emission and Star Forming Activity in the High Redshift Weak Line Quasars

We propose Herschel/SPIRE photometric observations of dust continuum emission in a sample of 19 weak line quasars (WLQs) at 2<z<5. These objects have weak or undetectable UV emission lines, with typical rest-frame Lya +N V equivalent widths <15 A. However, their broad band AGN continuum emission from is similar to that of normal radio-quiet/intermediate quasars, indicating that the weak UV line features are unlikely to be due to a relativistically boosted continuum. It is possible that these WLQs are young AGN systems, in which the emission line regions associated with high ionization lines have not yet fully formed. In this proposal, we request a systematic survey of the rest-frame far-infrared (FIR) dust continuum emission with SPIRE at 250 um, 350 um, and 500 um. The FIR emission from 30 to 60 K warm dust provides the most reliable estimates of star formation rates in the quasars/galaxies at high redshifts. Our goals are i) to determine the dust temperature, dust mass, and FIR luminosity of each object by fitting the SPIRE flux densities to an optically thin graybody model and constrain the star formation rates in these WLQs and ii) to obtain the mean FIR emission of the WLQs and understand how it compares to the normal/strong emission line quasars. The observations will be a crucial test of the hypothesis that if these WLQs are at a young evolutionary phase, in which the central AGN activity has just turned on and intense star formation is ongoing in the quasar hosts.

Lead Scientist: Ran Wang

Allocated time: 4.8 hours

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Dust Emission in the Starburst Quasar Host Galaxies at Redshift 6

Our group have been carrying out a systematic survey of the star formation and ISM properties in the host galaxies of z~6 quasars, and strong millimeter dust continuum and highly-excited molecular gas have been discovered in the host galaxies of about 30% of quasars at z~6, indicating the presence of massive star formation coeval with rapid supermassive black hole (SMBH) accretion in these earliest quasar host galaxies close to end of cosmic reionization. In this proposal, we request Herschel/SPIRE photometric observations of the rest-frame FIR continuum emission from three of the millimeter bright z~6 quasars. The FIR emission from star formation-heated warm dust provides the most reliable measurement of the star formation rate in the quasar host galaxies at the highest redshift. The SPIRE observation samples the peak of the FIR SED from quasars/galaxies at z~6, and thus, are critical in the study of dust temperature, dust mass, FIR luminosity and star formation rate in these ealiest quasar-starburst systems. We have an approved ALMA Cycle 0 project of image the [C II] fine structure line and 1mm dust continuum emission and measure the distribution of the star formation in these three objects (and another two z~6 quasars observed in an existing Herschel Key Program). The accurate measurements of star formation rates with SPIRE and spatial distribution/surface densities with ALMA will put key constraints on the early growth of the quasar spheroidal host galaxies at the earliest epoch. We also require PACS photometric observation of the 100 um and 160 um dust continuum emission from one of the three objects, J2310+1855, at z=6.002. This object is a rare Low ionization Broad Absorption Line quasar, but show very bright millimeter continuum and molecular CO line emission from the quasar host. The PACS observation will measure the rest-frame mid-infrared continuum emission and allow us to investigate the emission properties of the AGN-powered hot dust torus in the LoBAL systems at the highest redshift.

Lead Scientist: Ran Wang

Allocated time: 3.1 hours

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Dark Gas in M31

In order to understand the physics and evolution of galaxies, accurate measurements of their gas content are absolutely crucial. The standard method is to estimate the mass of the atomic phase from the 21-cm line and the mass of the molecular component from the CO 1-0 line. Recent Planck and Fermi results imply that there might be as much CO-dark molecular gas as is detected in the CO line. The existence of a significant phase of the ISM that is not traced by the CO/HI method has obvious implications for extragalactic astronomy, because all present and planned observational programmes to connect the star-formation rates of galaxies to their interstellar gas reservoirs are based on the standard CO/HI method.We have recently used Herschel to observe M31, the other big spiral galaxy in the Local Group, in five photometric bands. By comparing the dust column-density to the gas column-density estimated from the CO/HI, we have shown there are regions in M31 where there also appear to be substantial amounts of dark gas. The only way to unambiguously demonstrate its presence is to detect it directly. We therefore propose to observe 400-arcmin2 of M31 in the [CII] 158-micron line. These observations will provide a clean test of the 'dark gas' hyopthesis. This large survey of [CII] over a significant area of the closest big spiral, together with the existing CO and HI maps, will provide the most comprehensive dataset for studying all phases of the ISM in a normal spiral galaxy until SPICA. Together with the existing Herschel observations, the new data will make possible many projects to study the astrophysics of the ISM and the connections between star formation and the different phases of the ISM.

Lead Scientist: Stephen Eales

Allocated time: 43.7 hours

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Probing Shocks and Heating Mechanisms in the Mice Galaxies with Herschel

Models and observations have established the importance of major mergers in reshaping spirals and fueling starbursts and supermassive nuclear black holes, but much less is known about the redistribution, heating and the fate of dust and gas during the merger event. The Mice (NGC4676) is a rare pair of local galaxies caught in the early merger stage of heating a vast amount of molecular gas in one merger companion while generating intense starbursts in the other companion. Roughly 170 Myrs after the first encounter, the two companions appear optical similar but show extremely different contributions from the PAH, the warm and the cold molecular gas emission, so that the responsible heating mechanism remains a mystery. The proposed PACS and SPIRE spectroscopy, together with our Spitzer IRS data, will unveal the origin of this dichotomy in the ISM (e.g. the relative contributions of shocks versus UV heating). A strong tracer for shock excitation is an enhanced [OI] compared to H_2 and [CII] emission as well as an enhanced excitation of the high-J (>6-5) CO transitions and the detection of water lines. The combined power of high spatial resolution mid-, far-infrared imaging and spectroscopy as well as our CO interferometry, NIR, and optical data allows us to link the dominant coolant of the interstellar medium, PDRs, shocks, and ionized gas properties to the starlight, the dust, the warm and the cold molecular gas. The Mice galaxies offer an ideal test case for studying the interplay between star-formation and the ISM in a interaction driven environment. Herschel observations of this galaxy pair will provide a view on a rare local example of a brief phase (~100 Myrs) in the evolution of a major merger where shocks dominate the H_2 emission and the individual nuclei have extremely different spectral and physical properties.

Lead Scientist: Sebastian Haan

Allocated time: 9.4 hours

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Hydrogen Fluoride Absorption Toward Luminous Infrared Galaxies

We propose to carry out a HIFI survey of the fundamental transition of hydrogen fluoride (HF) at 1.232 THz toward 16 nearby IRAS-bright galaxies to probe their ISM physical conditions. Our proposal is motivated by recent Herschel observations revealing ubiquitous absorption by HF in the Milky Way galaxy. The HF J=1-0 transition has been observed in the spectrum of almost every bright continuum source in the Galactic plane and reveled to be an extremely sensitive probe of the diffuse molecular gas. We intend to make use of this unique probe by conducting a high spectral resolution (10-20 km/s) HIFI absorption survey toward continuum-bright external galactic nuclei exhibiting a wide range of physical properties (AGN, starbursts, mergers). HF is chemically very strongly bound and therefore resistant to photodissociation. Our study is facilitated by this resistance of HF molecules to destruction, which will occur in the extreme environments in the galactic nuclei. HF will thus be a very useful probe in regions of the ISM where more traditional gas probes, such as CO, are more prone to error (e.g., the use of the X-factor). With the simplifying assumption that all fluorine is likely to be locked up in HF, and that the HF molecules will reside in the ground rotational state, we can measure the hydrogen column density and mass of the nearby IRAS-bright galaxies. Observations of the local galaxies proposed here is the first step toward using HF as a tracer of the gas in high-redshift galaxies. By looking at extragalactic continuum-bright nuclei, we will also be able, through the use of the HIFI Wide Band Spectrometer, to simultaneously search for absorption through the Milky Way halo cloud population. Here, the rapid formation rate of HF and its strong molecular bond will allow us to detect HF absorption toward the tenuous and quiescent mostly HI clouds making up the galactic halo. These diffuse, cold regions may not otherwise be detectable in CO emission or other commonly uses tracers.

Lead Scientist: Steven Lord

Allocated time: 25.2 hours

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Far infrared emission from red quasars - a test of quasar mode feedback at z=2

Quasar mode feedback is thought to be a crucial ingredient in galaxy formation for luminous merging and star-bursting systems at high redshift. The energy from the emergent active nucleus is thought to cause significant gas outflows, reducing the available free gas reservoir for future star formation. It is currently unknown which observational state best corresponds to the stage at which this "blowout should occur. We intend to test one possible source population for this transition phase, by studying the dust content in a small, statistically complete sample of K-band selected reddened quasars from the AUS survey. All lie in the redshift range 1.5<z<2.5, the peak of quasar activity in "typical" galaxies. If the model is correct these galaxies should be in transition from actively star forming to passively heated dust, and should therefore show both far infrared colour and luminosity correlations with optical colour.

Lead Scientist: Stuart Lumsden

Allocated time: 14 hours

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Star Formation and ISM properties in the lowest metal-poor galaxies observed by Herschel

A remarkable result to date is our recent SHINING detection of the [CII] line with PACS in the ultra-metal-poor galaxies: IZw18 and SBS0335-052 (1/40th and 1/50 solar metallicity) giving us the best opportunity to study the star formation and ISM properties under the most extreme metal-poor conditions we have in our local universe - conditions similar to primordial ISM at very high redshift. SBS0335-052 and IZw18 are the most metal-poor galaxies that will ever be observed by Herschel. In spite of similar metallicities, the 2 galaxies are very different in star formation rates and MIR and FIR luminosities, suggesting that metallicity is not the most important parameter controlling star formation activity. We ask here for complementary [OI] 63 um and [OIII] 88 um observations to be able to interpret the [CII] detection in terms of ionised and neutral gas properties. These galaxies are not detected in CO and we believe that the [CII] is probing the molecular gas not traced by CO - the 'dark molecular gas' which could be a significant reservoir of fuel for the star formation in low metallicity galaxies. Our [CII] observations along with these followup lines, can provide a means to unveil this suspected reservoir of CO-free molecular gas. The [CII] detection along with these 10.2h of observations requested in this proposa, will shed unique, new insight on extremely low metallicity conditions for star formation and also help provide a standard calibration for getting a handle at the molecular gas reservoir in the high redshift lowest metallicity galaxies which will be a focus for ALMA studies.

Lead Scientist: Suzanne Madden

Allocated time: 10.2 hours

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Molecular Outflows in Gas-Rich Mergers: The IR-Faint QSOs in the Final Merger Phase

The role of galactic winds in gas-rich mergers is of crucial importance to understand galaxy and supermassive black hole evolution. In the past year, our group has had three major scientific breakthroughs in this area: (1) The PACS discovery of powerful molecular OH winds in several ULIRGs, including Mrk 231. (2) The independent discovery from mm-wave CO interferometric observations in Mrk 231 of a spatially resolved molecular wind with estimated mass outflow rate ~4x larger than the star formation rate. (3) The detection from optical IFU observations of an equally powerful wide-angle neutral-gas outflow in this same object. These powerful outflows may be the long-sought "smoking gun" of quasar mechanical feedback purported to transform gas-rich mergers. Indeed, we see possible trends of increasing outflow velocities and decreasing depletion time scales with increasing AGN luminosities in our PACS data. The approved OT1 extension of this program to quasar-dominated ULIRGs will allow us to test these trends. However, by design, this sample does not contain any "classic" IR-faint QSOs in the critical late merger phases when the quasar has finally gotten rid of its natal cocoon and the effects of feedback are predicted to subside. So here we request 37.2h to obtain high-S/N OH 119 um spectra of 5 IR-faint quasar-dominated late stage mergers. We have a comprehensive set of multiwavelength data on all of these objects, including crucial spatially resolved optical neutral-gas absorption spectroscopy. We will look for trends between the basic measured properties of OH (incidence of absorption, kinematics, column densities) and host/evolutionary indicators. In cases of kinematic match between OH features and spatially resolved neutral-gas clouds, we will be able to infer the masses and kinetic energies of these outflows. Measured velocities in excess of ~1000 km/s or inferred mass outflow rates much larger than the star formation rates would be telltale signs of AGN-driven winds.

Lead Scientist: Sylvain Veilleux

Allocated time: 37.2 hours

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Exploring the Dust Content of Galactic Winds with Herschel: The Dwarf Galaxy Population

We propose to extend our OT1 PACS imaging survey of galactic winds in nearby star-forming galaxies to the poorly explored but critically important low-mass end of the galaxy mass function. Following our OT1 strategy, we will obtain very deep PACS 70/160 micron data to map the detailed distribution of cold (T<100 K) dust in a small but representative sample of dwarf galaxies that are known to host outflows. These data will be compared to state-of-the-art, 3D numerical simulations of superwinds and predicted PACS fluxes. Direct and indirect evidence shows that dust is present on large (kiloparsec) scales in outflows in some starburst galaxies. However, this dust has never been mapped at wavelengths of 70-160 microns, and its geometry, mass, and energy are almost completely unknown. Recent spectacular SPIRE results on M82, as well as our own Spitzer IRAC 8-micron and MIPS 24-micron maps of the targeted wind galaxies, suggest that this survey will yield exciting new insights on the cold dust in these outflows. We will ascertain the significance of dusty superwinds in the context of outflow physics and the impact of the outflows on the host galaxies and the IGM. We will compare the distribution, mass, and energy of the cold dust to optical emission-line and absorption-line, mid-infrared, X-ray, and radio data compiled by us and other groups. As in OT1, we note that several of our targets are being mapped with PACS and SPIRE as part of key programs (KPs). However, the objectives of these programs are heterogeneous and often neglect the importance of outflow science. This is reflected in the depth of the observations at the critical shorter wavelengths, near the peak of the IR SED: the PACS KP data will not be able to detect the FIR emission expected from a M82-like wind in our galaxies. The proposed PACS survey will go nearly an order of magnitude deeper than the KP data and will complement the SPIRE portion of the KPs, while providing many advantages over the SPIRE data.

Lead Scientist: Sylvain Veilleux

Allocated time: 38.1 hours

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Molecular Gas Flows in Active Galaxies of the Local Volume

Mechanical feedback from AGN-driven winds has been purported to play a central role in the evolution of galaxies. However, past searches for AGN winds have been heavily biased, selecting the brightest sources in bands affected either by obscuration and/or contamination from the host galaxy light, and incomplete, probing only the ionized gas phase of these winds. Remarkably, recent results from our group and others have demonstrated that the neutral and molecular components of AGN-driven winds often dominate the mass, and thus dynamics and energetics, of these winds. To address these limitations, we have been conducting an extensive multiwavelength campaign, including crucial spatially resolved optical neutral-gas absorption spectroscopy, of all AGN detected in the very hard X-rays (14-195 keV) by Swift-BAT. The Swift-BAT survey is the least biased all sky survey for AGN with respect to host galaxy properties and obscuration in the line-of-sight, and thus it is superior to past surveys for understanding the role of AGN-driven winds in galaxies. Here we request 35.3 hrs to obtain high-S/N OH 119 um spectra of all BAT-AGN within the Local Volume to characterize molecular gas in/outflows in these systems. A distance limit of <50 Mpc is selected to provide the best possible scale (<200 pc/arcsec) while also sampling the AGN luminosity function up to quasar-like values without favoring IR-bright systems due to the need for high-S/N data at ~120 um. We will look for trends between the properties of OH 119 um (incidence of absorption, kinematics, column densities), the AGN (e.g., luminosity, accretion rate), and the host (e.g., morphology, star formation rate, extinction). In cases of kinematic match between OH features and spatially resolved neutral-gas clouds, we will be able to infer the masses and kinetic energies of these flows. Measured blueshifted velocities in excess of ~1000 km/s or inferred mass outflow rates much larger than the star formation rates would be telltale signs of AGN-driven winds.

Lead Scientist: Sylvain Veilleux

Allocated time: 35.3 hours

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Size is Not Everything: A PACS Emission Line Study of the Most Compact Infrared-luminous Galaxies

Recent results based on far-infrared (IR) data obtained with Herschel strongly suggest the existence of two modes of star formation that apply to low and high-redshift galaxies: a quiescent mode for disks (or main-sequence galaxies) and a starburst mode probably associated with more efficient nuclear, compact star formation. This dichotomy implies that the properties of the inter stellar medium (ISM) in these two types of systems must be substantially different. We have used the mid- to far-IR colors of galaxies as a proxy for their compactness to select a sample of local, compact luminous IR galaxies ((U)LIRGs; LIR >= 10^11 Lsun) from the IRAS 12-micron sample. Our sample of 73 compact (U)LIRGs includes both Seyfert galaxies as well as purely star-forming systems, and therefore is not biased towards active galaxies only. We will observe the key far-IR [CII]158, [OI]63, and [OIII]88 micron emission lines with Herschel/PACS and use models of photo-dissociation regions (PDRs), shocks, X-ray dissociation regions (XDRs), and dusty AGNs to derive the main physical parameters of the ISM in this important class of systems, which are not being targeted by any Herschel project. Our proposed galaxy sample bridges the gap between other studies focused on the analysis of local galaxies with a range of IR luminosities, mid- to far-IR colors, or more spatially extended IR emission, providing a wider view of the star formation and nuclear activity in local IR-bright galaxies in extreme environments, and thus adding a significant contribution to the Herschel legacy. The total time requested for achieving this goal is 89.8 hours.

Lead Scientist: Tanio Diaz-Santos

Allocated time: 45 hours

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The Synergy between Gas Dust and Star Formation for a Local Analog to z~1 Galaxy Evolution

We require Herschel PACS and SPIRE to study the ISM and cold dust component of a gas-rich, local LIRG undergoing inside-out disk-building -- HIZOA J0836-42. Spitzer reveals this galaxy to be PDR-dominated with gas and stellar properties, as well as specific star formation, more in common with z~1 systems than local LIRGs. We see evidence of neutral gas funneling into the mid-IR star-forming disk. Our observations will provide crucial (and unique) spatial information of the ISM and cold dust that may be common to z~1 "scaled-up" disk galaxies that have large reservoirs of neutral gas that they are actively converting into stars, in an extended disk. Knowledge of the active enrichment and metamorphosis of the ISM further out in the disk due to "new" star formation will enable us to form a cohesive picture of this mechanism of star formation and the role of gas, dust and (old and new) stars. We will search for evidence of "dark" molecular hydrogen inhabiting PDRs and making a hidden (and potentially crucial) contribution to the molecular mass that fuel in these systems. We can achieve this by mapping the cool dust component across the HI disk and obtaining maps of the key cooling lines, [OI]63 and [CII]158. These data will be complementary to our broader multi-wavelength study, and motivate future planned observations that aim to address our main science goal: understanding how the components of star formation (gas, dust, stars) interact and drive the fundamental gas-to-stars evolutionary cycle for galaxies in the early universe.

Lead Scientist: Thomas Jarrett

Allocated time: 11.3 hours

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Probing the Star Formation and ISM Evolution in M33.

We plan to investigate the interplay between the phases of the interstellar medium (ISM) and their evolution near star forming regions as a function of galactocentric distance by observing the far-infrared (far-IR) fine-structure lines of [CII] 158 micron, [OI] 63 micron and 146 micron, [NII] 122 micron,and [OIII] 88 micron in selected regions in the local-group galaxy M33. The transformation from atomic gas to molecular clouds and their subsequent destruction due to star formation is still poorly understood. Feedback from the young massive stars could heat the surrounding gas and thus hamper further star formation or compress the surrounding gas and thus increase the star formation effiency. The sequential evolution of cloud formation, star formation, and cloud destruction might depend on the internal as well as the external environmental conditions such as pressure, surface density, and metallicity, which change with galactocentric distance. The [CII], [OI], [OIII], and [NII] lines provide the best tools and M33 the optimal galaxy for this study. This proposal, for which we ask 12.5 hours observing time, is a follow-up project to the HerM33es key project.

Lead Scientist: Thomas Nikola

Allocated time: 12.5 hours

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Herschel observations of dust processing in meger galaxies

We propose to make PACS and SPIRE photometric mapping observations to obtain far-infrared (FIR) spectral energy distribution of the extended structures of the two merger galaxies NGC2782 and NGC7727, in which mid-infrared (MIR) observations with the Infrared Camera (IRC) onboard AKARI indicate the presence of PAH, and to investigate the dust processing associated with the merger event. Both galaxies show intriguing features at the mid-infrared band sensitive to the PAH features. The extended tail of NGC2782 seen at 7 micron is thought to have been produced by collision of a low-mass galaxy with the main galaxy about 200 Myr ago, while that seen in NGC7727 is a relic of the merger event of 1.2 Gyr ago. Both galaxies offer a unique opportunity to study dust processing in the merger event in different time scales. We propose to obtain FIR data to compare with the MIR data taken with the IRC, which will allow us to investigate the life cycle of dust grains in the ISM associated with violent events.

Lead Scientist: Takashi Onaka

Allocated time: 10.2 hours

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A `Rosetta Stone' for the cosmic X-ray and sub-mm backgrounds

We propose to measure FIR dust temperatures primarily for two X-ray absorbed, sub-mm bright, QSOs that may prove play the role of the `Rosetta Stone' in relating the sub-mm and X-ray backgrounds. Of 15 Chandra X-ray QSOs in the central ~100 sq. arcmin of the William Herschel Deep Field (WHDF), Bielby et al (2011) found that the only 2 that are identified as sub-mm sources are these absorbed QSOs at z=1.33 and z=2.12, with the latter being a narrow-lined Type 2 QSO. 11 X-ray unabsorbed QSOs were all undetected by LABOCA at 870 microns. Similar results were found previously by Page et al (2004). On the other hand, Hatziminaoglou et al (2010) recently found that many unabsorbed QSOs are clearly detected at 24-500 microns indicating warmer dust temperatures. One possibility is that the presence of cold gas and cold dust are correlated. This would predict that absorbed QSOs may only contain cold dust and we propose to test this prediction via PACS and SPIRE observations. If more cold gas does imply more cold dust then the Compton-thick QSOs needed to explain hard X-ray background may also explain the sub-mm background.

Lead Scientist: Tom Shanks

Allocated time: 9.4 hours

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Herschel observations of nearby mergers: understanding the process of star-formation along cosmic time

We propose to observe a small sample of nearby major mergers in three different merging stages with Herschel PACS and SPIRE photometers. The observations will allow us to derive the dust surface density and from this the total gas surface density. Together with already available tracers of the SFR (Spitzer 24 micron and GALEX FUV) we can study the Kennicutt-Schmidt law. High resolution data of the atomic gas content (partly already available and partly applied for at the EVLA) allow us furthermore to make a distinction between atomic and molecular gas. The derivation of the total gas mass via the dust emission involves less serious uncertainties than the use of CO as a tracer of the molecular gas.

With these observation we aim to address the open question why merging galaxies form stars at about a 10 times higher rate compared to their gas mass than quiescent galaxies. Our recent numerical models explain this by a higher turbulence which make the step from low-density to high-density (star--forming) gas more efficient. It makes specific prediction about the efficiency of the conversion from atomic to molecular gas, which directly affects the ratio between SFR and gas mass, as a function of merger stage. The selection of our sample and the proposed observations will allow us to test the predictions of the simulations and provide therefore an opportunity to improve our understanding of the physical processes underlying star-formation and of the cosmic star formation history

Lead Scientist: Ute Lisenfeld

Allocated time: 18.5 hours

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The Infrared View of Galaxy Evolution in the Environment of Groups: Unveiling the Dust

The so called Hickson Compact Groups (HCGs) occupy a unique position in the range of galaxy environments found in the local universe. While their density enhancements are high, close to those seen in rich clusters, the over-densities appear to be more locally contained. Dynamical interactions between the galaxies in the groups lead to consumption of the available gas, star formation, and a rapid evolution compared to field galaxies. It has been shown that HCGs contain significant amounts of dust, which has so far hampered a detailed understanding of those objects based on optical observations alone. Based on recent Spitzer observations, we have embarked in the first multiwavelength analysis of how groups affect galaxy evolution. We used the state-of-the-art theoretical models in order to interpret the complete spectral energy distribution of the galaxies from the UV to the IR, and compare them with samples of field galaxies and interacting systems. However, due to the proximity among the various galaxies in groups none of the past far-IR facilities (IRAS, Akari) had the angular resolution necessary to trace the far-IR emission of the individual group members, essential to determine the global energetics and dust content of the systems.

We propose to obtain deep broad-band far-IR images of 20 HCGs at various stages of evolution for which UV, optical, near-IR, and mid-IR data also exist. Herschel observations with their unique depth and high angular resolution, will enable us a) to accurately calculate the far-IR luminosity, dust mass and temperature of galaxies in HCGs in order to examine how the group environment affects them and b) determine the total "dust budget" in the groups by detecting the cold intragroup dust, studying its temperature, clumpiness, and spatial distribution. The proposed program requires a modest investment of 13.3 hrs.

Lead Scientist: Vassilis Charmandaris

Allocated time: 13.3 hours

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Star Formation and Molecular Gas in Distant Galaxies: SPIRE Spectroscopy of Quasar Absorption Systems

Absorption line systems in quasar spectra, especially the damped Lyman alpha (DLA) and sub-DLA absorbers, provide excellent venues for directly studying the interstellar medium (ISM) in distant galaxies, selected independently of the galaxy luminosities. DLAs/sub-DLAs provide most of the neutral gas reservoir for star formation at high redshifts. A few especially cold, dusty absorbers have been discovered using radio surveys and the Sloan Digital Sky Survey. These absorbers, far richer in dust/molecules than the general absorber population, give us rare opportunities to probe molecular gas and star formation at high redshift. Unfortunately, very few sub-mm observations exist for these unique quasar absorbers. Here we propose SPIRE spectroscopy of 5 quasars with strong absorbers that appear to have cold/dusty gas. The proposed data will efficiently cover a wide spectral range that is expected to be rich in transitions of many atomic and molecular species (e.g., C I, N II, CH+, CO, 13CO, C18O, H2O) at the absorber redshifts. These transitions will allow us to estimate molecular abundances, and physical conditions of the absorber gas such as temperature and density. Comparisons of these distant absorbers with Milky Way ISM will provide a step toward understanding how ISM evolves with time. The molecular lines will also give constraints on isotopic ratios such as 12CO/13CO, and the cosmic microwave background temperature at the absorber redshifts. Our data will also cover the redshifted [C II] 158 micron emission line, which can help to constrain the star formation rate in the absorber galaxies. The proposed data will thus provide several fresh insights into the stellar and interstellar content of distant galaxies, and pave the way for future ALMA observations. Additionally, the data will provide important constraints on the continuum SEDs of the background quasars. Herschel SPIRE is the only current instrument that can offer the wavelength coverage needed to efficiently observe the lines of interest.

Lead Scientist: Varsha Kulkarni

Allocated time: 28.9 hours

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Caught in the Middle: Post-Starbursts as Transitions from Ultraluminous Infrared Galaxies to Massive Ellipticals

One of the outstanding tasks in modern astrophysics is to uncover the physical mechanisms responsible for the observed tight correlation between super massive black hole mass, and host galaxy bulge mass and stellar velocity dispersion (M_BH-sigma relation). Numerical simulations invoke major mergers and interactions between massive, gas rich galaxies to reproduce the observed relation, along with the ULIRG number density, QSO luminosity function, black hole mass function and mass density. However, observational evidence for these suggested scenarios is either unavailable or inconclusive.

Here we propose to measure the far-infrared continuum and line properties of a unique sample of massive, dusty, obscured AGN, to reveal whether they are the descendants of ULIRGs and progenitors of massive elliptical galaxies. These 12 galaxies contribute around 10% of the total black hole accretion rate summed over a complete sample of nearly 17,000 local (z<0.07) galaxies, and thus represent a significant channel for black hole growth in the Universe. Their optical continuum suggests they underwent strong starbursts between 0.35 and 1Gyr ago. Their nebula emission line strengths, combined with a simple empirical model for the rate of decay of star formation following a starburst, predicts FIR luminosities during their starburst phase of 7e11-2e12 Lsun, implying that these were ULIRGS in the past. Herschel PACS+SPIRE observations will reveal whether this sample of unusual, dusty AGN is the much sought after ``transition'' phase between merger/ULIRG/starburst and elliptical galaxy.

Lead Scientist: Vivienne Wild

Allocated time: 9.7 hours

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Extremely-metal poor galaxies: mapping dust emission

The understanding of the interstellar medium (ISM) and star formation in the low-metallicity environment is crucial to constrain formation of stars and galaxies of the first generation. The local extremely low-metallicity galaxies (XMPGs) with Z<Zsun/20 offer the unique laboratory with nearly metal-free environment that mimics the condition in the early universe. Previous infrared studies have focused on their integrated properties due to their small sizes and faint brightness. The general conclusion is that they show dramatic different ISM and star formation properties from more metal-rich galaxies, and that a large diversity in the properties is also seen among XMPGs alone. The high resolution combined with its multiple far-IR bands of Herschel will revolutionize the study of ISM and star formation in XMPGs through the spatially-resolved images of dust properties (mass and temperature) and SFRs. By relating the dust and star formation properties to the local physical conditions, we can start to understand the underlying physical mechanisms that regulate ISM and star formation processes in the extremely low-metallicity environment. We propose to obtain deep map of the dust emission in three XMPGs with Herschel PACS and SPIRE photometer. These three objects are carefully selected to facilitate the spatially-resolved study, i.e. the large size and previous IR detections by Spitzer. Combined with a rich ancillary data, we will (1) model dust emission to derive dust properties and then relate it to the local physical properties; (2) derive reliable SFRs by combining IR-based obscured SFRs and UV-based unobscured ones, from which we then can understand the star formation processes at sub-kpc scales.

Lead Scientist: Yong Shi

Allocated time: 16.1 hours

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