Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Nature of the Faint Chandra X-ray Sources in the Galactic Centre   Recent Chandra observations have revealed a large population of faint X-ray
point sources in the Galactic Centre. The observed population consists of about
2000 faint sources in the luminosity range ~10^31-10^33 erg/s. The majority of
these sources (70%) are described by hard spectra, while the rest are rather
soft. The nature of these sources still remains unknown. Belczynski & Taam
(2004) demonstrated that X-ray binaries with neutron star or black hole
accretors may account for most of the soft sources, but are not numerous enough
to account for the observed number and X-ray properties of the faint hard
sources. A population synthesis calculation of the Galactic Centre region has
been carried out. Our results indicate that the numbers and X-ray luminosities
of intermediate polars are consistent with the observed faint hard Galactic
Centre population.

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The categories of this paper are: chao-dyn
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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: acc-phys
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The categories of this paper are: supr-con
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The categories of this paper are: hep-ph
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The categories of this paper are: math
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The categories of this paper are: plasm-ph
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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: hep-lat
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The categories of this paper are: nlin
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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: gr-qc
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The categories of this paper are: q-alg