The galaxy cluster Abell S1063, as imaged by the Hubble Space Telescope as part of the Frontier Fields program. The faint bluish glow is produced by stars ripped away from their host galaxies. This intracluster light mirrors the distribution of the dark matter shaping the cluster. Image: NASA/ESA and M. Montes (University of New South Wales, Sydney, Australia)
Dark matter, whatever it might be, makes up nearly 30 percent of the universe, providing the gravity that explains the unexpected behaviour of single galaxies and enormous clusters. Understanding how the mysterious material is distributed across the cosmos is a major topic of research.
Two astronomers from Spain and Australia have found a way to measure that distribution in galaxy clusters by studying the faint glow emitted by stars that have been stripped away from their host galaxies and float freely in intragalactic space. Over time, the stars end up where most of the mass of a cluster – mostly dark matter – resides.
“We have found a way to ‘see’ dark matter,” said Mireia Montes of the University of New South Wales, Australia, and lead author of a study in the Monthly Notices of the Royal Astronomical Society. “We have found ...