Gravothermal collapse in dark matter halos

A dark force, which is a necessary ingredient of self-interacting dark matter models, can lead to gravothermal collapse of dark matter in small mass halos. This talk will review the physics of gravothermal collapse and highlight new results pertaining to its dependence on particle physics models. Then we will examine a strong argument for why gravothermal collapse must occur for self-interacting dark matter models to be viable, and end with a discussion of gravitational lensing as a promising way to test these models.