The largest census of dust in local galaxies has been completed using data from ESA's Herschel space observatory, providing a huge legacy to the scientific community. Cosmic dust grains are a minor but fundamental ingredient in the recipe of gas and dust for creating stars and planets. But despite its importance, there is an incomplete picture of the dust properties in galaxies beyond our own Milky Way. Key questions include how the dust varies with the type of galaxy, and how it might affect our understanding of how galaxies evolve.
Before concluding its observations in April 2013, Herschel provided the largest survey of cosmic dust, spanning a wide range of nearby galaxies located 50-80 million light-years from Earth. The catalogue contains 323 galaxies with varying star formation activity and different chemical compositions, observed by Herschel's instruments across far-infrared and submillimetre wavelengths. A sample of these galaxies is displayed in a collage, arranged from dust-rich in the top left to dust-poor in the bottom right.
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).
© ESA/Herschel/HRS-SAG2 and HeViCS Key Programmes/Sloan Digital Sky Survey/ L. Cortese (Swinburne University)
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