Collage of galaxies in the Herschel Reference Survey at infrared/submillimeter wavelengths by Herschel (left) and at visible wavelengths from the Sloan Digital Sky Survey (SDSS, right). The Herschel image is colored with blue representing cold dust and red representing warm dust; the SDSS image shows young stars in blue and old stars in red. Together, the observations plot young, dust-rich spiral/irregular galaxies in the top left, with giant dust-poor elliptical galaxies in the bottom right.
Image credit: ESA/Herschel/HRS-SAG2 and HeViCS Key Programmes/Sloan Digital Sky Survey/ L. Cortese (Swinburne University)
Note: For more information, see Herschel Completes Largest Survey of Cosmic Dust in Local Universe and Herschel Survey in Infrared.