Event Details

Stellar streams are elongated, almost one-dimensional collection of stars that originate from the tidal disruption of globular clusters or dwarf galaxies merging into the Milky Way. Gravitational encounters between a stellar stream and dark matter subhalos will leave imprints in the stellar stream density which can be statistically analyzed to predict the properties of the impacting subhalos as well as the dark matter micro-physics, both of which are intimately related. Using recent data from Gaia and PanSTARRS on the GD-1 stream and CFHT data on the Pal 5 stream I constrain the overall abundance of subhalos within a Galactocentric radius of 20 kpc. Furthermore, in the case of dark matter being a thermal relic, I will show that by combining stellar stream constraints and dwarf satellite counts the dark matter particle mass should be > 6.3 keV at 95% confidence.