Astronomy & Astrophysics Seminar: What Do the Local Stars and Gas Teach Us about Dark Matter?

Abstract: 

Models of Dark Matter containing a dissipative subsector predict an enhanced local dark matter density within the Galactic disk, in additional to the standard Dark Matter halo. Constraints are placed on the parameter space of these models from observations of the local Milky Way. The first constraint comes from the kinematics of local stars. I will argue that most kinematic constraints quoted in the literature only apply to the dark matter halo but not to a dark disk. I will then show that the constraints that do apply to a dark disk may be highly sensitive non-equilibrium features in the tracer star populations. Recent constraints from Gaia data will also be discussed. Constraints are also placed from the distribution of local interstellar gas. Here, it is shown that a disk of dark matter may be needed to counter the effect of the gas’s magnetic pressure.

Seminar Organizer: Prof. Sara Beck