The characteristic black hole mass resulting from direct collapse in the
  early universe
  Black holes of a billion solar masses are observed in the infant universe a
few hundred million years after the Big Bang. The direct collapse of
protogalactic gas clouds in primordial halos with $\rm T_{vir} \geq 10^{4} K$
provides the most promising way to assemble massive black holes. In this study,
we aim to determine the characteristic mass scale of seed black holes and the
time evolution of the accretion rates resulting from the direct collapse model.
We explore the formation of supermassive black holes via cosmological large
eddy simulations (LES) by employing sink particles and following their
evolution for twenty thousand years after the formation of the first sink. As
the resulting protostars were shown to have cool atmospheres in the presence of
strong accretion, we assume here that UV feedback is negligible during this
calculation. We confirm this result in a comparison run without sinks. Our
findings show that black hole seeds with characteristic mass of $\rm 10^{5}
M_{\odot}$ are formed in the presence of strong Lyman Werner flux which leads
to an isothermal collapse. The characteristic mass is a about two times higher
in LES compared to the implicit large eddy simulations (ILES). The accretion
rates increase with time and reach a maximum value of 10 $\rm M_{\odot}/yr$
after $\rm 10^{4}$ years. Our results show that the direct collapse model is
clearly feasible as it provides the expected mass of the seed black holes.
