The formation and evolution of massive black hole seeds in the early
  Universe
  Tracking the evolution of high redshift seed black hole masses to late times,
we examine the observable signatures today. These massive initial black hole
seeds form at extremely high redshifts from the direct collapse of pre-galactic
gas discs. Populating dark matter halos with seeds formed in this fashion, we
follow the mass assembly history of these black holes to the present time using
a Monte-Carlo merger tree approach. Utilizing this formalism, we predict the
black hole mass function at high redshifts and at the present time; the
integrated mass density of black holes in the Universe; the luminosity function
of accreting black holes as a function of redshift and the scatter in observed,
local M-sigma relation. Comparing the predictions of the `light' seed model
with these massive seeds we find that significant differences appear
predominantly at the low mass end of the present day black hole mass function.
However, all our models predict that low surface brightness, bulge-less
galaxies with large discs are least likely to be sites for the formation of
massive seed black holes at high redshifts. The efficiency of seed formation at
high redshifts has a direct influence on the black hole occupation fraction in
galaxies at z=0. This effect is more pronounced for low mass galaxies. This is
the key discriminant between the models studied here and the Population III
remnant `light' seed model. We find that there exists a population of low mass
galaxies that do not host nuclear black holes. Our prediction of the shape of
the M-sigma relation at the low mass end and increased scatter has recently
been corroborated by observations.
