Title: Aspects of Rotating Black Holes in Dynamical Chern-Simons Gravity
Abstract: In this talk I will give an overview of recent and ongoing work regarding rotating black holes in dynamical Chern-Simons (dCS) gravity. dCS gravity is a well motivated modified theory of gravity which has been extensively studied in gravitational and cosmological contexts. I will first discuss unique geometric structures, `the Chern-Simons caps,' which slowly rotating black holes in dCS gravity were recently found to possess. Motivated by the dCS caps, I will then discuss superradiance in the context of slowly rotating dCS black holes and show that there are corrections to the usual solution for a Kerr black hole. Lastly, I will comment on the observable implications for these corrections and point towards avenues for future work.
Oren Slone (Princeton/NYU)
Title: Orbital Evolution of Satellite Galaxies in Self-Interacting Dark Matter Models
Abstract: In this talk I describe a recent publication [arXiv:2108.03243], where we demonstrate that dark matter self interactions can leave distinctive signatures on the properties of satellite galaxies around Milky Way-like hosts through their impact on tidal stripping, ram pressure, and gravothermal collapse. We delineate the regions of self-interacting dark matter parameter space—specified by interaction cross section and a velocity scale—where each of these effects dominates, and show how the relative mass loss depends on the satellite's initial mass, density profile and orbit. We obtain novel, conservative constraints in this parameter space using Milky Way satellite galaxies with notably high central densities and small pericenter distances. Our results for self-interacting dark matter models, in combination with constraints from clusters of galaxies, favor velocity-dependent cross sections that lead to gravothermal core collapse in the densest satellites.