The Formation of Supermassive Black Holes from Population III.1 Seeds.
  I. Cosmic Formation Histories and Clustering Properties
  We calculate cosmic distributions in space and time of the formation sites of
the first, "Pop III.1" stars, exploring a model in which these are the
progenitors of all supermassive black holes (SMBHs), seen in the centers of
most large galaxies. Pop III.1 stars are defined to form from primordial
composition gas in dark matter minihalos with $\sim10^6\:M_\odot$ that are
isolated from neighboring astrophysical sources by a given isolation distance,
$d_{\rm{iso}}$. We assume Pop III.1 sources are seeds of SMBHs, based on
protostellar support by dark matter annihilation heating that allows them to
accrete a large fraction of their minihalo gas, i.e., $\sim10^5\:M_\odot$.
Exploring $d_{\rm{iso}}$ from $10 - 100\:\rm{kpc}$ (proper distances), we
predict the redshift evolution of Pop III.1 source and SMBH remnant number
densities. The local, $z=0$ density of SMBHs constrains $d_{\rm{iso}}\lesssim
100\:\rm{kpc}$ (i.e., $3\:\rm{Mpc}$ comoving distance at $z\simeq30$). In our
simulated ($\sim60\:\rm{Mpc}$)$^3$ comoving volume, Pop III.1 stars start
forming just after $z=40$. Their formation is largely complete by $z\simeq25$
to $20$ for $d_{\rm{iso}}=100$ to $50\:\rm{kpc}$. We follow source evolution to
$z=10$, by which point most SMBHs reside in halos with $\gtrsim10^8\:M_\odot$.
Over this period, there is relatively limited merging of SMBHs for these values
of $d_{\rm{iso}}$. We also predict SMBH clustering properties at $z=10$:
feedback suppression of neighboring sources leads to relatively flat angular
correlation functions.
