Title: Radiative effects during the assembly of direct collapse black holes,
Abstract: We perform a post-processing radiative feedback analysis on a 3D ab initio
cosmological simulation of an atomic cooling halo under the direct collapse
black hole (DCBH) scenario. We maintain the spatial resolution of the
simulation by incorporating native ray-tracing on unstructured mesh data,
including Monte Carlo Lyman-alpha (Ly{\alpha}) radiative transfer. DCBHs are
born in gas-rich, metal-poor environments with the possibility of Compton-thick
conditions, $N_H \gtrsim 10^{24} {\rm cm}^{-2}$. Therefore, the surrounding gas
is capable of experiencing the full impact of the bottled-up radiation
pressure. In particular, we find that multiple scattering of Ly{\alpha} photons
provides an important source of mechanical feedback after the gas in the
sub-parsec region becomes partially ionized, avoiding the bottleneck of
destruction via the two-photon emission mechanism. We provide detailed
discussion of the simulation environment, expansion of the ionization front,
emission and escape of Ly{\alpha} radiation, and Compton scattering. A sink
particle prescription allows us to extract approximate limits on the
post-formation evolution of the radiative feedback. Fully coupled Ly{\alpha}
radiation hydrodynamics will be crucial to consider in future DCBH simulations.