Milky Way Satellites: Probes of Dark Matter Microphysics

Apr 26, 2019 - 4:00 pm to 5:00 pm

Campus, Varian 312

Ethan Nadler (Stanford)

As luminous tracers of the smallest observationally accessible dark matter halos, faint satellite galaxies orbiting the Milky Way have the potential to dramatically improve our understanding of dark matter microphysics. However, the confounding effects of baryonic physics on halo abundances and galaxy formation have made the interpretation of the observed MW satellite population unclear. I will describe a forward model for the MW satellite population based on high-resolution zoom-in simulations that marginalizes over these astrophysical effects and accounts for the relevant numerical and observational uncertainties. This method significantly improves current constraints on warm and/or interacting dark matter models, including sterile neutrinos, ultra-light axions, and self-interacting dark matter. I will discuss limits on DM-baryon scattering in WIMP-like models that improve upon CMB and Lyman-alpha forest analyses by several orders of magnitude.