Reionization with Simba: How much does astrophysics matter in modeling
  cosmic reionization?
  Traditional large-scale models of reionization usually employ simple
deterministic relations between halo mass and luminosity to predict how
reionization proceeds. We here examine the impact on modelling reionization of
using more detailed models for the ionizing sources as identified within the
$100~{\rm Mpc/h}$ cosmological hydrodynamic simulation Simba, coupled with
post-processed radiative transfer. Comparing with simple (one-to-one) models,
the main difference of using Simba sources is the scatter in the relation
between dark matter halos and star formation, and hence ionizing emissivity. We
find that, at the power spectrum level, the ionization morphology remains
mostly unchanged, regardless of the variability in the number of sources or
escape fraction. Our results show that simplified models of ionizing sources
remain viable to efficiently model the structure of reionization on
cosmological scales, although the precise progress of reionization requires
accounting for the scatter induced by astrophysical effects.
