Speaker
Description
Observations of substructure is one of the strongest probes of dark matter microphysics. At the low mass end of parameter space, ultralight dark matter produces wavelike interference patterns in the dark matter density which can impact a wide variety of observations from subhalo abundance, to lensing, to the stellar dispersion of galaxies, etc. We investigate how this wavelike structure looks near phase space caustics. These are features in phase space that occur in systems such as the splashback radius, merging subhalos, and stellar streams. In this talk we will discuss how caustic structures form and how their density changes for ultralight dark matter. We will show the results of simulations in our recent paper (arxiv.2506.02400) and discuss potential observational prospects.
