Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Study of the Cir X--1 Broad Band Spectrum at Orbital Phases Close to the
  Apoastron   We report on the results of a BeppoSAX (1.8--200 keV) observation of the
peculiar X-ray binary source Circinus X--1 (Cir X--1) at the orbital phases
between 0.61 and 0.63. We find that three components are needed to fit the
broad band spectrum: a blackbody component, at a temperature of $\sim 0.6$ keV,
a Comptonized component, with a seed-photon temperature of $\sim 1.2$ keV,
electron temperature of $\sim 6$ keV and optical depth of $\sim 1.7$, and a
power-law component dominating the spectrum at energies higher than 20 keV. We
interpret the blackbody as the emission from the accretion disk, while the
Comptonized component probably comes from a corona surrounding the inner part
of the system. This spectrum is different from that observed at the periastron
(Iaria et al. 2001a) because of the presence of the blackbody component. We
discuss the implications of this difference and the presence of the power-law
component.

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The categories of this paper are: physics
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ex
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: cmp-lg
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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
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The categories of this paper are: funct-an
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The categories of this paper are: math
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The categories of this paper are: atom-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-bio