Spiral Galaxy M66

Basic Information

What is this?

A barred-spiral galaxy

Where is it in the sky?

One of the "Leo Triplet" of galaxies in the constellation of Leo the Lion

How big is it?

About the same size as our own Milky Way galaxy

How far away is it?

About 35 million light years

What do the colours represent?

This is an image taken by a single channel - the SPIRE 250 micron channel

The barred-spiral galaxy Messier 66 (or M66 for short) is the largest galaxy in the "Leo Triplet" of galaxies, and trio of galaxies in the constellation of Leo. M66 is a barred spiral galaxy, which means it has spiral arms, in this case two large ones, connected by a bar running through the centre of the galaxy. The spiral arms are being pulled out of shape by the two nearby galaxies which complete the triplet. Herschel is not seeing the stars in the spiral arms and the bar, but instead the dust and gas which are being heated up by the stars.

In the background of the image, there are dozens of smaller blobs. These are not image artefacts, or even foreground stars, but much more distant galaxies - too far away for Herschel to see other than as small fuzzy blobs. Observations with SPIRE provide information on how warm and how far away the galaxies are, as well as an estimate of how much star formation is occuring in each galaxy.

M66 as seen by Herschel and Spitzer

The image on the left is a comparison of the previous best image at far-infrared wavelengths, taken by NASA's Spitzer satellite. Herschel has a much larger mirror (3.5m compared with 0.7m) and so can see the galaxy in much finer resolution.

.

Detailed Information

Object Name: 
M66
Type of Object: 
Barred-spiral galaxy
Image Scale: 
About 10 arcminutes across
Coordinates: 
Right Ascension: 11h 20m 15.0s ; Declination: +12° 59′ 30″
Constellation: 
Leo
Instrument: 
SPIRE
Observation Date/Time: 
Fri, 16/04/2010 - 12:41
Wavelengths: 
250 microns
Distance of Object: 
About 35 million light years
Date of Release: 
10/07/2009