Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A broadband X-ray spectral study of the intermediate-mass black hole
  candidate M82 X-1 with NuSTAR, Chandra and Swift   M82 X-1 is one of the brightest ultraluminous X-ray sources (ULXs) known,
which, assuming Eddington-limited accretion and other considerations, makes it
one of the best intermediate-mass black hole (IMBH) candidates. However, the
ULX may still be explained by super-Eddington accretion onto a stellar-remnant
black hole. We present simultaneous NuSTAR, Chandra and Swift/XRT observations
during the peak of a flaring episode with the aim of modeling the emission of
M82 X-1 and yielding insights into its nature. We find that thin-accretion disk
models all require accretion rates at or above the Eddington limit in order to
reproduce the spectral shape, given a range of black hole masses and spins.
Since at these high Eddington ratios the thin-disk model breaks down due to
radial advection in the disk, we discard the results of the thin-disk models as
unphysical. We find that the temperature profile as a function of disk radius
($T(r)\propto r^{-p}$) is significantly flatter ($p=0.55^{+ 0.07}_{- 0.04}$)
than expected for a standard thin disk ($p=0.75$). A flatter profile is instead
characteristic of a slim disk which is highly suggestive of super-Eddington
accretion. Furthermore, radiation hydrodynamical simulations of super-Eddington
accretion have shown that the predicted spectra of these systems are very
similar to what we observe for M82 X-1. We therefore conclude that M82 X-1 is a
super-Eddington accretor. Our mass estimates inferred from the inner disk
radius imply a stellar-remnant black hole ($M_{\rm BH}=26^{+9}_{-6} M_{\odot}$)
when assuming zero spin, or an IMBH ($M_{\rm BH}=125^{+45}_{-30} M_{\odot}$)
when assuming maximal spin.

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The categories of this paper are: funct-an
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The categories of this paper are: eess
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The categories of this paper are: comp-gas
1
The categories of this paper are: cs
2
The categories of this paper are: math
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The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom
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The categories of this paper are: physics
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-th
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The categories of this paper are: nlin
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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: solv-int