Digging the Dirt on Galaxies - the nearby Universe

This image of some nearby galaxies shows the power of Herschel ATLAS in finding local objects.  We can see spiral arms in galaxies but we are not looking at stars here, but rather the dust which is heated up by the stars.  The bright blue colours are showing regions which are warmer because they are being heated up by stars. With Herschel ATLAS, we will detect galaxies forming today and a few billion years ago (at redshifts less than 0.5), long enough ago to be interesting but still close enough that we can use optical telescopes to study the environments and other properties of the galaxies. Bizarrely we know more about the distant Universe in these wave-bands than our own backyard. This is because previous sub-mm telescopes looked very hard in small regions of sky, a method which takes in a lot of the distant Universe but very little of the stuff nearby. Herschel-ATLAS is the first 'blind' survey of dust and obscured star formation over the past 5 billion years of cosmic history and will fill in the 'missing link' in how galaxies evolved from being as they were in the distant past to how we see them today. Herschel-ATLAS can do this because of the incredibly fast speed at which the Herschel SPIRE camera can make images of the sky, the wide area of the survey is key to our ability to find nearby galaxies.