Fervent: Chemistry-coupled, ionising and non-ionising radiative feedback
  in magnetohydrodynamical simulations
  We introduce a radiative transfer code module for the magnetohydrodynamical
adaptive mesh refinement code FLASH 4. It is coupled to an efficient chemical
network which explicitly tracks the three hydrogen species H, H_2, H+ as well
as C+ and CO. The module is geared towards modeling all relevant thermal
feedback processes of massive stars, and is able to follow the non-equilibrium
time-dependent thermal and chemical state of the present-day interstellar
medium as well as that of dense molecular clouds. We describe in detail the
implementation of all relevant thermal stellar feedback mechanisms, i.e.
photoelectric, photoionization and H_2 dissociation heating as well as pumping
of molecular hydrogen by UV photons. All included radiative feedback processes
are extensively tested. We also compare our module to dedicated
photon-dominated region (PDR) codes and find good agreement in our modeled
hydrogen species once our radiative transfer solution reaches equilibrium. In
addition, we show that the implemented radiative feedback physics is
insensitive to the spatial resolution of the code and show under which
conditions it is possible to obtain well-converged evolution in time. Finally,
we briefly explore the robustness of our scheme for treating combined ionizing
and non-ionizing radiation.
