Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Unusual X-ray Binaries of the Globular Cluster NGC 6652   Our 5 ks Chandra ACIS-S observation of the globular cluster NGC 6652 detected
7 X-ray sources, 3 of which are previously unidentified. This cluster hosts a
well-known bright low-mass X-ray binary, source A (or XB 1832-330). Source B
shows unusual rapid flaring variability, with an average L_X(0.5-10 keV)
~2*10^{34} ergs/s, but with minutes-long flares up to L_X=9*10^{34} ergs/s. Its
spectrum can be fit by an absorbed power-law of photon index Gamma~1.24, and
hardens as the countrate decreases. This suggests that part or all of the
variation might be due to obscuration by the rim of a highly inclined accretion
disk. Sources C and D, with L_X ~10^{33} ergs/s, have soft and unusual spectra.
Source C requires a very soft component, with a spectrum peaking at 0.5 keV,
which might be the hot polar cap of a magnetically accreting polar cataclysmic
variable.
  Source D shows a soft spectrum (fit by a power-law of photon index ~2.3) with
marginal evidence for an emission line around 1 keV; its nature is unclear. The
faint new sources E, F, and G have luminosities of 1-2*10^{32} ergs/s, if
associated with the cluster (which is likely). E and F have relatively hard
spectra (consistent with power-laws with photon index ~1.5). G lacks soft
photons, suggesting absorption with N_H>10^{22} cm^{-2}.

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The categories of this paper are: patt-sol
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The categories of this paper are: math-ph
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The categories of this paper are: nlin
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The categories of this paper are: hep-ex
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The categories of this paper are: cmp-lg
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The categories of this paper are: eess
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The categories of this paper are: dg-ga
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The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
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The categories of this paper are: supr-con
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The categories of this paper are: solv-int
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The categories of this paper are: cs
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The categories of this paper are: adap-org
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The categories of this paper are: bayes-an
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The categories of this paper are: stat
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The categories of this paper are: gr-qc