Events Daily

Tuesday, December 14, 2021

Precision cosmology with dwarf galaxies
Justin Read, University of Surrey
Event Type: Astro Seminar
Time: 2:00 PM - 3:15 PM
Location: 726 Broadway, 940, CCPP Seminar
Abstract: Dark matter makes up most of the mass of the Universe but remains mysterious. I discuss recent progress in constraining its properties by measuring: 1) its distribution inside tiny dwarf galaxies; and 2) by counting the numbers of tiny dwarf galaxies in the nearby Universe. I present observational evidence that dark matter at the centres of dwarfs is pushed outwards by baryonic feedback during galaxy formation, and that this process may act even in the very smallest "ultra-faint" dwarfs. I go on to show how the densest dwarfs – that are least affected by such baryonic processes – provide competitive constraints on "self-interacting" and "wave"-like dark matter. I then look at dwarf galaxy counts. This holds the promise of unparalleled constraints on warm dark matter models and the small scale matter power spectrum. However, realising this promise requires a detailed understanding of how stars and gas map to the very smallest dark matter halos. I show how the latest cosmological simulations are making significant progress in calculating this. Finally, I present a novel and fully data-driven approach to the problem that will allow future surveys to place robust constraints on the mass of a thermal relic dark matter particle.