Daniel J. Whalen, Chris L. Fryer
The existence of 10$^9$ M$_{\odot}$ black holes (BH) in massive galaxies by
$z \sim 7$ is one of the great unsolved mysteries in cosmological structure
formation. One leading model argues that they originate from much smaller seeds
at high redshift and then accrete at the Eddington limit down to the epoch of
reionization, which requires that they have constant access to rich supplies of
fuel. Because early numerical simulations suggested that many first stars had
masses $\gtrsim 100$ M$_{\odot}$, the supermassive black hole (SMBH) seeds in
this model were 100 - 300 M$_{\odot}$ black holes formed by Pop III stars at $z
\sim 20$. However, there is growing numerical and observational evidence that
most Pop III stars were tens of solar masses, not hundreds, and consequently
that 20 - 140 M$_{\odot}$ black holes may have been much more plentiful at high
redshift. We have examined low-mass Pop III black holes as potential seeds of
SMBH and find that the mass range for possible seeds is severely constrained.
Progenitors of black holes above $\sim $100 M$_{\odot}$ disperse their fuel
supply prior to the birth of the BH. Natal kicks imparted to 20 - 40
M$_{\odot}$ Pop III BHs during formation eject these BHs from their halos and
hence their fuel supply, precluding them from constant Eddington-limit growth.
Inefficient radiative feedback and halo mass statistics favor early rapid
accretion by 40 - 140 M$_{\odot}$ BH, and these may be the characteristic
masses of Pop III SMBH seeds.
View original:
http://arxiv.org/abs/1112.4598
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