Formation of intermediate-mass black holes in circumnuclear regions of galaxies

Abstract

Recent high-resolution X-ray imaging studies have discovered possible candidates of intermediate-mass black holes with masses of M• ∼ 102-4 M(fisheye sign) in circumnuclear regions of many (disk) galaxies. It is known that a large number of massive stars are formed in a circumnuclear giant HII region. Therefore, we propose that a continual merger of compact remnants left from these massive stars is responsible for the formation of such an intermediate-mass black hole within a timescale of ∼ 109 yr. A necessary condition is that several hundreds of massive stars are formed in a compact region with a radius of a few parsecs.