Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The formation of compact massive self-gravitating discs in metal-free
  haloes with virial temperatures of ~ 13000-30000 K   We have used the hydrodynamical AMR code ENZO to investigate the dynamical
evolution of the gas at the centre of dark matter haloes with virial velocities
of ~ 20 - 30 kms and virial temperatures of ~ 13000-30000 K at z ~ 15 in a
cosmological context. The virial temperature of the dark matter haloes is above
the threshold where atomic cooling by hydrogen allows the gas to cool and
collapse. We neglect cooling by molecular hydrogen and metals, as may be
plausible if H_2 cooling is suppressed by a meta-galactic Lyman-Werner
background or an internal source of Lyman-Werner photons, and metal enrichment
has not progressed very far. The gas in the haloes becomes gravitationally
unstable and develops turbulent velocities comparable to the virial velocities
of the dark matter haloes. Within a few dynamical times it settles into a
nearly isothermal density profile over many decades in radius losing most of
its angular momentum in the process. About 0.1 - 1 % of the baryons, at the
centre of the dark matter haloes, collapse into a self-gravitating, fat,
ellipsoidal, centrifugally supported exponential disc with scale-length of ~
0.075-0.27 pc and rotation velocities of 25-60 kms. We are able to follow the
settling of the gas into centrifugal support and the dynamical evolution of the
compact disc in each dark matter halo for a few dynamical times. The dynamical
evolution of the gas at the centre of the haloes is complex. In one of the
haloes the gas at the centre fragments into a triple system leading to strong
tidal perturbations and eventually to the in-fall of a secondary smaller clump
into the most massive primary clump. The formation of centrifugally supported
self-gravitating massive discs is likely to be an important intermediary stage
en route to the formation of a massive black hole seed.

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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-th
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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-alg
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The categories of this paper are: nlin
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The categories of this paper are: adap-org
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The categories of this paper are: eess
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The categories of this paper are: quant-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: plasm-ph
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The categories of this paper are: math-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-lat