Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Supermassive Black Hole Formation at High Redshifts via Direct Collapse:
  Physical Processes in the Early Stage   We use numerical simulations to explore whether direct collapse can lead to
the formation of SMBH seeds at high-z. We follow the evolution of gas within DM
halos of 2 x 10^8 Mo and 1 kpc. We adopt cosmological density profiles and
j-distributions. Our goal is to understand how the collapsing flow overcomes
the centrifugal barrier and whether it is subject to fragmentation. We find
that the collapse leads either to a central runaway or to off-center
fragmentation. A disk-like configuration is formed inside the centrifugal
barrier. For more cuspy DM distribution, the gas collapses more and experiences
a bar-like perturbation and a central runaway. We have followed this inflow
down to ~10^{-4} pc. The flow remains isothermal and the specific angular
momentum is efficiently transferred by gravitational torques in a cascade of
nested bars. This cascade supports a self-similar, disk-like collapse. In the
collapsing phase, virial supersonic turbulence develops and fragmentation is
damped. For larger initial DM cores the timescales become longer. In models
with more organized initial rotation, a torus forms and appears to be supported
by turbulent motions. The evolution depends on the competition between two
timescales, corresponding to the onset of the central runaway and off-center
fragmentation. For less organized rotation, the torus is greatly weakened, the
central accretion timescale is shortened, and off-center fragmentation is
suppressed --- triggering the central runaway even in previously `stable'
models. The resulting SMBH masses lie in the range 2 x 10^4 Mo - 2 x 10^6 Mo,
much higher than for Population III remnants. We argue that the above upper
limit appears to be more realistic mass. Corollaries of this model include a
possible correlation between SMBH and DM halo masses, and similarity between
the SMBH and halo mass functions, at time of formation.

1
The categories of this paper are: cs
18
The categories of this paper are: econ
3
The categories of this paper are: physics
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
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The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
0
The categories of this paper are: hep-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-th
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The categories of this paper are: comp-gas
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The categories of this paper are: mtrl-th
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The categories of this paper are: math