The reionization of galactic satellite populations
  We use high resolution simulations of the formation of the local group
post-processed by a radiative transfer code for UV photons, to investigate the
reionization of the satellite populations of an isolated Milky Way-M31 galaxy
pair in a variety of scenarios. We use an improved version of ATON which
includes a simple recipe for radiative feedback. In our baseline models,
reionization is initiated by low mass, radiatively regulated haloes at high
redshift, until more massive haloes appear, which then dominate and complete
the reionization process. We investigate the relation between reionization
history and present-day positions of the satellite population. We find that the
average reionization redshift (zr) of satellites is higher near galaxy centers
(MW and M31). This is due to the inside-out reionization patterns imprinted by
massive haloes within the progenitor during the EoR, which end up forming the
center of the galaxy. Thanks to incomplete dynamical mixing during galaxy
assembly, these early patterns survive down to present day, resulting in a a
clear radial gradient in the average satellites reionization redshift, up to
the virial radius of MW and M31 and beyond. In the lowest emissivity scenario,
the outer satellites are reionized about 180 Myr later than the inner
satellites. This delay decreases with increasing source model emissivity, or in
the case of external reionization by Virgo or M31, because reionization happens
faster overall, and becomes spatially quasi-uniform at the highest emissivity.
