Gravothermal collapse of Self-Interacting Dark Matter halos as the Origin of Intermediate Mass Black Holes in Milky Way satellites

Understand

Milky Way (MW) satellites exhibit a diverse range of internal kinematics, reflecting in turn a diverse set of subhalo density profiles.

• These profiles include large cores and dense cusps, which any successful dark matter model must explain simultaneously.
• A plausible driver of such diversity is self-interactions between dark matter particles (SIDM) if the cross section passes the threshold for the gravothermal collapse phase at the characteristic velocities of the MW satellites.
• In this case, some of the satellites are expected to be hosted by subhalos that are still in the classical SIDM core phase, while those in the collapse phase would have cuspy inner profiles, with a SIDM-driven intermediate mass black hole (IMBH) in the centre as a consequence of the runaway collapse.