Speakers
Description
The properties of dark matter halos and subhalos on sub-galactic scales, below 10^9 solar masses, depend on the formation mechanism, mass, and possible interactions of the dark matter particle, as well as the initial conditions for structure formation determined by the primordial matter power spectrum and inflation. As such, inferences of the abundance and density profiles of low-mass halos can be recast as constraints on fundamental physics. Strong gravitational lensing by galaxies provides a direct, purely gravitational means of inferring the properties of dark matter structure down to roughly 10^7 solar masses with existing data. I will describe recent work that uses measurements of image magnifications in quads to infer properties of dark substructure in strong lens systems. I will then discuss what these inferences can tell us about the nature of dark matter, including potential self-interactions, the free-streaming length, and connections to the primordial matter power spectrum.
