12:00–1:00 pm Zoom
Daniel Gilman (University of Toronto) "Fundamental dark matter physics with strong gravitational lenses"
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 low-mass halos. In particular, existing measurements of image magnifications in quadruple-image lenses (quads) can be used to infer the abundance and concentrations of dark matter halos down to roughly 10^7 solar masses. I will describe a forward modeling inference framework that uses measurements of image magnifications in quads to infer properties of dark substructure in strong lens systems, including both subhalos around the main deflector’s host dark matter halo, and structure distributed along the line of sight. I will then review applications of this inference method to models of warm dark matter, self-interacting dark matter, and the primordial matter power spectrum.
