Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Beyond Jcrit: a critical curve for suppression of H2-cooling in
  protogalaxies   Suppression of H2-cooling in early protogalaxies has important implications
for the formation of supermassive black holes seeds, the first generation of
stars, and the epoch of reionization. This suppression can occur via
photodissociation of H2 (by ultraviolet Lyman-Werner [LW] photons) or by
photodetachment of H-, a precursor in H2 formation (by infrared [IR] photons).
Previous studies have typically adopted idealised spectra, with a blackbody or
a power-law shape, in modeling the chemistry of metal-free protogalaxies, and
utilised a single parameter, the critical UV flux, or Jcrit, to determine
whether H2-cooling is prevented. This can be misleading, and that independent
of the spectral shape, there is a critical curve in the (kLW , kH^- ) plane,
where kLW and kH^- are the H2-dissocation rates by LW and IR photons, which
determines whether a protogalaxy can cool below ~1000 Kelvin. We use a one-zone
model to follow the chemical and thermal evolution of gravitationally
collapsing protogalactic gas, to compute this critical curve, and provide an
accurate analytical fit for it. We improve on previous works by considering a
variety of more realistic Pop III or Pop II-type spectra from population
synthesis models and perform fully frequency-dependent calculations of the
H2-photodissociation rates for each spectrum. We compute the ratio kLW/kH^- for
each spectrum, as well as the minimum stellar mass M_star, for various IMFs and
metallicities, required to prevent cooling in a neighboring halo a distance d
away. We provide critical M_star/d2 values for suppression of H2-cooling, with
analytic fits, which can be used in future studies.

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The categories of this paper are: nucl-th
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The categories of this paper are: atom-ph
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The categories of this paper are: math-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: funct-an
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The categories of this paper are: plasm-ph
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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: physics
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The categories of this paper are: quant-ph
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
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The categories of this paper are: stat
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The categories of this paper are: cmp-lg
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The categories of this paper are: cs
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The categories of this paper are: supr-con