QQ01: V: Medium: Cosmic Rays, AGN, & Galaxies

Tue. April 25, 12:36 p.m. – 12:48 p.m. CDT

Virtual Room 1

IMBHs may form in dense star clusters via the merger of stellar-mass black holes or the collapse of very massive stars. Within these dense environments, tidal disruption events (TDEs) of cluster stars by IMBHs are likely to produce electromagnetic signatures with a long-lived super-Eddington accretion phase. In this talk, I will present the outcomes of hydrodynamic calculations of TDEs of Main-Sequence stars by IMBHs. Depending upon the distance at the closest approach, these events can lead to a fully disrupted star or partially disrupted bound/unbound remnant.  We find that stronger encounters lead to increased mass loss at the first pericenter passage, in many cases ejecting the partially disrupted star on an unbound orbit. For encounters that initially produce a bound system, with only partial stripping of the star, the fraction of mass stripped from the star increases with each subsequent pericenter passage and a stellar remnant of finite mass is ultimately ejected in all cases. We also find that the number of successive close passages before ejection decreases as we go from the stellar-mass black hole to the intermediate-mass black hole regime. For instance, after an initial encounter right at the classical tidal disruption limit, a 1M_? star undergoes 16 (5) pericenter passages before ejection from a 10M_? (100M_?) black hole. Observations of consecutive electromagnetic flares from these repeated close passages could in principle be used to determine the mass of the black hole, thus possibly proving the existence of intermediate-mass black holes.