Herschel survey in infrared and visible

Collage of galaxies in the Herschel Reference Survey at infrared/submillimetre wavelengths by Herschel (left) and at visible wavelengths from the Sloan Digital Sky Survey (SDSS, right). The Herschel image is coloured 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.