Royal Astronomical Society | 2019 Jan 03
Scientists have found evidence that dark matter can be heated up and moved around, as a result of star formation in galaxies. The findings provide the first observational evidence for the effect known as ‘dark matter heating’, and give new clues as to what makes up dark matter. ...Star formation in tiny dwarf galaxies can slowly 'heat up' the dark matter, pushing
it outwards. The left image shows the hydrogen gas density of a simulated dwarf
galaxy. The right image shows the same for a real dwarf galaxy, IC 1613.
(Credit: J. Read et al)
In the new work, scientists ... set out to hunt for evidence for dark matter at the centres of nearby dwarf galaxies. Dwarf galaxies are small, faint galaxies that are typically found orbiting larger galaxies like our own Milky Way. They may hold clues that could help us to better understand the nature of dark matter.
Dark matter is thought to make up most of the mass of the universe. However since it doesn’t interact with light in the same way as normal matter, it can only be observed through its gravitational effects. The key to studying it may however lie in how stars are formed in these galaxies.
When stars form, strong winds can push gas and dust away from the heart of the galaxy. As a result, the galaxy’s centre has less mass, which affects how much gravity is felt by the remaining dark matter. With less gravitational attraction, the dark matter gains energy and migrates away from the centre, an effect called ‘dark matter heating’. ...
Dark Matter Heats Up in Dwarf Galaxies ~ J. I. Read, M. G. Walker, P. Steger
- Monthly Notices of the RAS (online 03 Jan 2019) DOI: 10.1093/mnras/sty3404
arXiv.org > astro-ph > arXiv:1808.06634 > 20 Aug 2018