Speaker
Description
Dark matter halos and subhalos less massive than 10^9 solar masses hold the key to understanding the nature of dark matter, including its formation mechanism, particle mass, and possible interactions. In particular, self-interacting dark matter (SIDM) prescribes a dynamic evolution of halo density profiles that distinguishes it from cold dark matter. This process begins with core formation, and ends with gravothermal catastrophe, or core collapse. Core collapse transforms halos into extremely efficient gravitational lenses. Focusing on SIDM with attractive interaction potentials, I will argue that resonances in the cross section, which increase its amplitude by over an order of magnitude, can trigger core collapse in low-mass subhalos and field halos. By analyzing the relative image magnifications of quadruply-imaged quasars, I will present constraints on the abundance of core-collapsed halos and field halos, and cast this inference in terms of resonant SIDM. I will conclude by discussing future prospects for this kind of analysis with forthcoming data from JWST.
