Cosmic Dawn II (CoDa II): a new radiation-hydrodynamics simulation of
  the self-consistent coupling of galaxy formation and reionization
  Cosmic Dawn II (CoDa II) is a new, fully-coupled radiation-hydrodynamics
simulation of cosmic reionization and galaxy formation and their mutual impact,
to redshift $z < 6$. With $4096^3$ particles and cells in a 94 Mpc box, it is
large enough to model global reionization and its feedback on galaxy formation
while resolving all haloes above $10^8$ M$_{\odot}$. Using the same hybrid
CPU-GPU code RAMSES-CUDATON as CoDa I in Ocvirk et al. (2016), CoDa II modified
and re-calibrated the subgrid star-formation algorithm, making reionization end
earlier, at $z \gtrsim 6$, thereby better matching the observations of
intergalactic Lyman-alpha opacity from quasar spectra and electron-scattering
optical depth from cosmic microwave background fluctuations. CoDa II predicts a
UV continuum luminosity function in good agreement with observations of high-z
galaxies, especially at $z = 6$. As in CoDa I, reionization feedback suppresses
star formation in haloes below $\sim 2 \times 10^9$ M$_{\odot}$, though
suppression here is less severe, a possible consequence of modifying the
star-formation algorithm. Suppression is environment-dependent, occurring
earlier (later) in overdense (underdense) regions, in response to their local
reionization times. Using a constrained realization of $\Lambda$CDM constructed
from galaxy survey data to reproduce the large-scale structure and major
objects of the present-day Local Universe, CoDa II serves to model both global
and local reionization. In CoDa II, the Milky Way and M31 appear as individual
islands of reionization, i.e. they were not reionized by the progenitor of the
Virgo cluster, nor by nearby groups, nor by each other.
