Supermassive Black Hole Formation Inside Primordial Black Hole Clusters

A model of supermassive black hole formation inside clusters of primordial black holes is developed. We suppose that small mass fraction of the Universe, $∼10−3,$ is composed of compact clusters of primordial (relic) black holes, produced during a phase transition at early epochs. These clusters are the centres of dark matter condensation. We model the formation of protogalaxies with masses about $2×108 M⊙$ at redshift $z = 15.$ These induced protogalaxies contain central black holes with mass $∼105 M⊙$ and look like dwarf spheroidal galaxies with a central density spike. The multiple coalescences of primordial black holes results in formation of supermassive black holes in galactic centers. The observed correlation between the masses of central black holes and velocity dispersion in the galactic bulges is reproduced in this model.