Cores in Dwarf Galaxies from Fermi Repulsion

Cores in Dwarf Galaxies from Fermi Repulsion
James Unwin, University of Illinois at Chicago / Simons Center for Geometry and Physics, Stony Brook
Date and time: Tue, Apr 02, 2019 - 2:30pm
Location: LGRT 419B
Category: ACFI Seminar
Abstract:

Cold dark matter provides a remarkably good description of cosmology and astrophysics. However, observations connected with small scales might be in tension with this framework. In particular, structure formation simulations suggest that the density profiles of dwarf spheroidal galaxies should exhibit cusps, in contrast to observations. I will show that Fermi repulsion can explain the observed cored density profiles in dwarf galaxies for sub-keV fermionic dark matter.  While in conventional dark matter scenarios, such sub-keV thermal dark matter would be excluded by free streaming bounds, I will argue that these constraints are ameliorated in models with dark matter at lower temperature than conventional thermal scenarios and discuss aspects of model building.