How to Quench a Dwarf Galaxy: The Impact of Inhomogeneous Reionization
  on Dwarf Galaxies and Cosmic Filaments
  We use the SPHINX suite of high-resolution cosmological radiation
hydrodynamics simulations to study how spatially and temporally inhomogeneous
reionization impacts the baryonic content of dwarf galaxies and cosmic
filaments. The SPHINX simulations simultaneously model an inhomogeneous
reionization, follow the escape of ionising radiation from thousands of
galaxies, and resolve haloes well below the atomic cooling threshold. This
makes them an ideal tool for examining how reionization impacts star formation
and the gas content of dwarf galaxies. We compare simulations with and without
stellar radiation to isolate the effects of radiation feedback from that of
supernova, cosmic expansion, and numerical resolution. We find that the gas
content of cosmic filaments can be reduced by more than 80% following
reionization. The gas inflow rates into haloes with $M_{vir}<10^8M_{\odot}$ are
strongly affected and are reduced by more than an order of magnitude compared
to the simulation without reionization. A significant increase in gas outflow
rates is found for halo masses $M_{vir}<7\times10^7M_{\odot}$. Our simulations
show that inflow suppression, rather than photoevaporation, is the dominant
mechanism by which the baryonic content of high-redshift dwarf galaxies is
regulated. At fixed redshift and halo mass, there is a large scatter in the
halo baryon fractions that is entirely dictated by the timing of reionization
in the local region surrounding a halo which can change by $\Delta z>3$ at
fixed mass. Finally, although the gas content of high-redshift dwarf galaxies
is significantly impacted by reionization, we find that most haloes with
$M_{vir}<10^8M_{\odot}$ can remain self-shielded and form stars long after
reionization, until their local gas reservoir is depleted, suggesting that
local group dwarf galaxies do not necessarily exhibit star formation histories
that peak prior to $z=6$...
