Radiation hydrodynamical simulations of the birth of intermediate-mass black holes in the first galaxies

ABSTRACT The leading contenders for the seeds of z > 6 quasars are direct-collapse black holes (DCBHs) forming in atomically cooled haloes at ? 20. However, Lyman–Werner (LW) UV background required to form DCBHs 105 M? extreme, about 104 J21, and may have been rare early universe. Here we investigate formation intermediate-mass (IMBHs) under moderate LW backgrounds 100 500 which were much more common times. These allow grow a few 106–107 virial temperatures nearly K before collapsing, but do not completely sterilize them H2. Gas collapse then proceeds via Ly? rapid H2 cooling rates that 10–50 times those normal Pop III star-forming haloes, less than purely haloes. stars accreting such become blue hot, find their ionizing radiation limits final masses 1800–2800 they later IMBHs. Moderate thus produced IMBHs far greater numbers