Lyman α radiation hydrodynamics of galactic winds before cosmic reionization

The dynamical impact of Lyman alpha ( Ly alpha) radiation pressure on galaxy formation depends on the rate and duration of momentum transfer between Ly alpha photons and neutral hydrogen gas. Although photon trapping has the potential to multiply the effective force, ionizing radiation from stellar sources may relieve the Ly alpha pressure before appreciably affecting the kinematics of the host galaxy or efficiently coupling Ly alpha photons to the outflow. We present self-consistent Ly alpha radiation-hydrodynamics simulations of high-z galaxy environments by coupling the Cosmic Ly alpha Transfer code (COLT) with spherically symmetric Lagrangian frame hydrodynamics. The accurate but computationally expensive Monte Carlo radiative transfer calculations are feasible under the one-dimensional approximation. The initial starburst drives an expanding shell of gas from the centre and in certain cases, Ly alpha feedback significantly enhances the shell velocity. Radiative feedback alone is capable of ejecting baryons into the intergalactic medium (IGM) for protogalaxies with a virial mass of M-vir less than or similar to 108M(circle dot). We compare the Ly alpha signatures of Population III stars with 10(5) K blackbody emission to that of direct collapse black holes with a non-thermal Compton-thick spectrum and find substantial differences if the Ly alpha spectra are shaped by gas pushed by Ly alpha radiation-driven winds. For both sources, the flux emerging from the galaxy is reprocessed by the IGM such that the observed Ly alpha luminosity is reduced significantly and the time-averaged velocity offset of the Ly alpha peak is shifted redward.