SPRAI: Coupling of radiative feedback and primordial chemistry in moving
  mesh hydrodynamics
  In this paper we introduce a new radiative transfer code SPRAI (Simplex
Photon Radiation in the Arepo Implementation) based on the SimpleX radiation
transfer method. This method, originally used only for post-processing, is now
directly integrated into the Arepo code and takes advantage of its adaptive
unstructured mesh. Radiated photons are transferred from the sources through
the series of Voronoi gas cells within a specific solid angle. From the photon
attenuation we derive corresponding photon fluxes and ionization rates and feed
them to a primordial chemistry module. This gives us a self-consistent method
for studying dynamical and chemical processes caused by ionizing sources in
primordial gas. Since the computational cost of the SimpleX method does not
scale directly with the number of sources, it is convenient for studying
systems such as primordial star-forming halos that may form multiple ionizing
sources.
