Photon trapping enables super-Eddington growth of black hole seeds in galaxies at high redshift

Abstract

We identify a physical mechanism that would have resulted in rapid, obscured growth of seed supermassive black holes in galaxies at z ≳ 6. Specifically, we find that the density at the centre of typical high-redshift galaxies was at a level where the Bondi accretion rate implies a diffusion speed of photons that was slower than the gravitational infall velocity, resulting in photons being trapped within the accretion flow and advected into the black hole. We show that there is a range of black hole masses (Mbh ~ 103-5MO) where the accretion flow traps radiation, corresponding to black holes that were massive enough to generate a photon trapping accretion flow, but small enough that theirBond..