The abundance and dark matter structure of galaxies in alternative dark matter models

Strong dark matter interactions are proposed to alleviate the tension between observations and theoretical predictions in CDM. Among different interaction channels, self-interacting dark matter (SIDM) models have received considerable attention. However, most models and simulations have so far neglect the contribution of the baryons.  First, I will present a combination of results from idealized SIDM simulations that explore the effect of a baryonic disk/bulge on the shape and density profile of dark matter halos. We find that the inclusion of baryons in the models help alleviate two of the long standing issues within CDM: i) the diversity of rotation curves on the scale of dwarf galaxies and ii) the high sphericity measured for the dark matter halo of our own Milky Way. In the second part of my talk I will discuss an analytical model to study the effects  of dark matter-dark radiation interactions on the abundance of faint galaxies at high redshifts.

Speaker: Omid Sameie, UC Riverside