Monsters in the Dark: Predictions for Luminous Galaxies in the Early
  Universe from the BlueTides Simulation
  Using deep Hubble and Spitzer observations Oesch et al. (2016) have
identified a bright ($M_{\rm UV}\approx -22$) star forming galaxy candidate at
$z \approx 11$. The presence of GN-$z11$ implies a number density $\sim
10^{-6}\,{\rm Mpc^{-3}}$, roughly an order of magnitude higher than the
expected value based on extrapolations from lower redshift. Using the
unprecedented volume and high resolution of the BlueTides cosmological
hydrodynamical simulation, we study the population of luminous rare objects at
$z > 10$. The luminosity function in BlueTides implies an enhanced number of
massive galaxies, consistent with the observation of GN-$z11$. We find about 30
galaxies at $M_{\rm UV}\approx -22$ at $z = 11$ in the BlueTides volume,
including a few objects about 1.5 magnitudes brighter. The probability of
observing GN-$z11$ in the volume probed by Oesch et al. (2016) is $\sim 13$ per
cent. The predicted properties of the rare bright galaxies at $z = 11$ in
BlueTides closely match those inferred from the observations of GN-$z11$.
BlueTides predicts a negligible contribution from faint AGN in the observed
SED. The enormous increase in volume surveyed by WFIRST will provide
observations of $\sim1000$ galaxies with $M_{\rm UV} < -22$ beyond $z = 11$ out
to $z = 13.5$.
