Evolution of Supermassive Black Holes from Cosmological Simulations
  The correlations between the mass of supermassive black holes and properties
of their host galaxies are investigated through cosmological simulations. Black
holes grow from seeds of 100 solar masses inserted into density peaks present
in the redshift range 12-15. Seeds grow essentially by accreting matter from a
nuclear disk and also by coalescences resulting from merger episodes. At z=0,
our simulations reproduce the black hole mass function and the correlations of
the black hole mass both with stellar velocity dispersion and host dark halo
mass. Moreover, the evolution of the black hole mass density derived from the
present simulations agrees with that derived from the bolometric luminosity
function of quasars, indicating that the average accretion history of seeds is
adequately reproduced . However, our simulations are unable to form black holes
with masses above $10^9 M_{\odot}$ at $z\sim 6$, whose existence is inferred
from the bright quasars detected by the Sloan survey in this redshift range.
