Formation Process of Supermassive Blackholes

From a Stellar-Dynamical Viewpoint

Abstract

Recently, an “intermediate mass” black hole (IMBH) was found in the central region of galaxy M82 through observations made by ASCA, Chandra and SUBARU. This is the first finding of a black hole with the mass more than 100 solar mass but significantly less than 1 million solar mass, and, as such, has completely changed our understanding of the formation process of massive blackholes. We describe our new scenario in which IMBHs serve as the “missing link” between small and massive black holes. IMBHs first form in young compact star clusters through runaway merging of massive stars. While these IMBHs are forming, the host star clusters sink toward the galactic nucleus through dynamical friction, and upon evaporation deposit their IMBHs near the galactic center. The IMBHs then form binaries and eventually merge via gravitational radiation, forming an SMBH.