Early Black Holes in Cosmological Simulations: Luminosity Functions and
  Clustering Behaviour
  We examine predictions for the quasar luminosity functions (QLF) and quasar
clustering at high redshift (z > 4.75) using MassiveBlack, our new hydrodynamic
cosmological simulation which includes a self-consistent model for black hole
growth and feedback. We show that the model reproduces the Sloan QLF within
observational constraints at z >= 5. We find that the high-z QLF is consistent
with a redshift-independent occupation distribution of BHs among dark matter
halos (which we provide) such that the evolution of the QLF follows that of the
halo mass function. The sole exception is the bright-end at z=6 and 7, where
BHs in high-mass halos tend to be unusually bright due to extended periods of
Eddington growth caused by high density cold flows into the halo center. We
further use these luminosity functions to make predictions for the number
density of quasars in upcoming surveys, predicting there should be ~119+-28
(~87+-28) quasars detectable in the F125W band of the WIDE (DEEP) fields of the
Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) from
z=5-6, ~19+-7 (~18+-9) from z=6-7, and ~1.7+-1.5 (~1.5+-1.5) from z=7-8. We
also investigate quasar clustering, finding that the correlation length is
fully consistent with current constraints for Sloan quasars (r_0~17 h^{-1} Mpc
at z=4 for quasars above m_i = 20.2), and grows slowly with redshift up to z=6
(r_0~22 h^{-1} Mpc). Finally, we note that the quasar clustering strength
depends weakly on luminosity for low L_BH, but gets stronger at higher L_BH as
the BHs are found in higher mass halos.
