Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Comparison of spectral models for disc truncation in the hard state of
  GX 339-4   We probe models of disc truncation in the hard spectral state of an outburst
of the well-known X-ray transient GX 339--4. We test a large number of
different models of disc reflection and its relativistic broadening, using two
independent sets of codes, and apply it to a \textit{Rossi X-ray Timing
Explorer} spectrum in the rising part of the hard state of the 2010/11
outburst. We find our results to be significantly model-dependent. While all of
the models tested show best-fits consistent with truncation, some models allow
the disc to extend close to the innermost stable circular orbit (ISCO) and some
require substantial disc truncation. The different models yield a wide range in
best-fit values for the disc inclination. Our statistically best model has a
physical thermal Comptonization primary continuum, requires the disc to be
truncated at a radius larger than or equal to about two ISCO radii for the
maximum dimensionless spin of 0.998, and predicts a disc inclination in
agreement with that of the binary. Our preferred models have moderate Fe
abundance, $\gtrsim$2 times solar. We have also tested the effect of increasing
the density of the reflecting medium. We find it leads to an increase in the
truncation radius, but also to an increase in the Fe abundance, opposite to a
previous finding.

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The categories of this paper are: supr-con
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The categories of this paper are: math-ph
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The categories of this paper are: chao-dyn
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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: acc-phys
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The categories of this paper are: mtrl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: nlin
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The categories of this paper are: q-alg
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The categories of this paper are: eess
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The categories of this paper are: physics
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: cs
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The categories of this paper are: hep-th