Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Luminosity-dependent spectral and timing properties of the accreting
  pulsar GX 304-1 measured with INTEGRAL   Context: Be/X-ray binaries show outbursts with peak luminosities up to a few
times $10^{37}\,$erg/s, during which they can be observed and studied in
detail. Most (if not all) Be/X-ray binaries harbour accreting pulsars, whose
X-ray spectra in many cases contain cyclotron resonant scattering features
related to the magnetic field of the sources. Spectral variations as a function
of luminosity and of the rotational phase of the neutron star are observed in
many accreting pulsars. Aims: We explore X-ray spectral and timing properties
of the Be/X-ray binary GX 304-1 during an outburst episode. Specifically, we
investigate the behavior of the cyclotron resonant scattering feature, the
continuum spectral parameters, the pulse period, and the energy- and
luminosity-resolved pulse profiles. We combine the luminosity-resolved spectral
and timing analysis to probe the accretion geometry and the beaming patterns of
the rotating neutron star. Methods: We analyze the INTEGRAL data from the two
JEM-X modules, ISGRI and SPI, covering the January-February 2012 outburst,
divided in six observations. We obtain pulse profiles in two energy bands,
phase-averaged and phase-resolved spectra for each observation. Results: We
confirm the positive luminosity-dependence of the cyclotron line energy in GX
304-1, and report a dependence of the photon index on luminosity. Using a
pulse-phase connection technique, we find a pulse period solution valid for the
entire outburst. Our pulse-phase resolved analysis shows, that the centroid
energy of the cyclotron line is varying only slightly with pulse phase, while
other spectral parameters show more pronounced variations. Our results are
consistent with a scenario in which, as the pulsar rotates, we are exploring
only a small portion of its beam pattern.

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The categories of this paper are: chem-ph
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
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The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: q-fin
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The categories of this paper are: math-ph
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The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
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The categories of this paper are: econ
2
The categories of this paper are: math
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The categories of this paper are: hep-th
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The categories of this paper are: funct-an
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc