Astrophysical Probes of Dark Matter
A key aspect of my work in astrophysics focuses on identifying the nature of the dark matter. Our understanding of the formation of dark matter halos in the Universe has improved to the degree that we are able to place constraints on the microscopic properties of the dark matter through the (macroscopic) shapes of dark matter halos. This happens when the dark matter has self-interactions that affect the way structure forms in the Universe. I have been exploring the dynamics of self-interacting dark matter, where in the extreme case, dark matter can sink to the center of the halo via fusion processes. Models of dark matter can also inject additional power on small scales, and lead to dense minihalos. While there are currently few constraints on the clumpiness of dark matter on small scales, we are exploring the possibility of detecting small gravitationally induced delays in timing of light from millisecond pulsars. These theories of self-interacting dark matter go hand in hand with models of dark matter probed with quantum materials.
Stars are also probes of fundamental physics, as has long been recognized. These days we are continuing to find new and exotic applications of our understanding of stellar theory to fundamental physics. For example, dark matter with a primordial particle antiparticle asymmetry may collect in the center of a neutron star and cause the formation of a black hole.