Speaker
Description
In the nightmare scenario, the underlying particle physics of dark matter as
well as our cosmological history could be discerned purely gravitationally by studying
the gravitational substructure that dark matter collapses into. In this talk, I present stringent
limits on this substructure, arising from the non-observation of heat exchange between
substructure contained in ultra-faint dwarfs, and the stars, which would cause the expansion
of the stellar half-light radius to values larger than what is observed. These limits also translate to orders-of-magnitude improvement in limits on the primordial power spectrum down to the kpc scale. These results also have consequences for dark matter self-interactions as well as the lower limit on plausible dark matter mass.
