Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Transient Sub-Eddington Black Hole X-ray Binary Candidate in the Dust
  Lanes of Centaurus A   We report the discovery of a bright X-ray transient, CXOU J132527.6-430023,
in the nearby early-type galaxy NGC 5128. The source was first detected over
the course of five Chandra observations in 2007, reaching an unabsorbed
outburst luminosity of 1-2*10^38 erg/s in the 0.5-7.0 keV band before returning
to quiescence. Such luminosities are possible for both stellar-mass black hole
and neutron star X-ray binary transients. Here, we attempt to characterize the
nature of the compact object. No counterpart has been detected in the optical
or radio sky, but the proximity of the source to the dust lanes allows for the
possibility of an obscured companion. The brightness of the source after a >100
fold increase in X-ray flux makes it either the first confirmed transient
non-ULX black hole system in outburst to be subject to detailed spectral
modeling outside the Local Group, or a bright (>10^38 erg/s) transient neutron
star X-ray binary, which are very rare. Such a large increase in flux would
appear to lend weight to the view that this is a black hole transient. X-ray
spectral fitting of an absorbed power law yielded unphysical photon indices,
while the parameters of the best-fit absorbed disc blackbody model are typical
of an accreting ~10 Msol black hole in the thermally dominant state.

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The categories of this paper are: stat
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
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The categories of this paper are: math
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The categories of this paper are: q-bio
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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: acc-phys
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: eess
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-fin
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The categories of this paper are: hep-th