Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Looking into the heart of a beast: the black hole binary LS 5039   LS 5039 is a relatively close microquasar consisting of a late O-type star
and a compact object (very possibly a black hole) on a highly eccentric orbit
with a period of 3.9 days. The high X-ray, gamma-ray and radio luminosity
indicate light-matter interaction, which arise from the stellar wind of the
primary star accreting toward the black hole. Former examinations suggest that
LS 5039 could be a prototype of wind-fed high mass X-ray binaries (WXBs) with
diskless main sequence O primaries. Now there is a great chance to better
understand the configuration and the physical processes in the exotic system.
In July 2009 LS 5039 was followed by the Canadian MOST space telescope to get
ultraprecise photometric data in a month-long semi-continuous time series.
Parallel to this, we have taken simultaneous high-resolution optical spectra
using the 2.3m ANU telescope of the Siding Spring Observatory, supplemented
with further data obtained in early August 2009 with the same instrument. Here
we present the first results from the new echelle spectra, which represent the
best optical spectroscopy ever obtained for this intriguing system. We
determined fundamental orbital and physical parameters of LS 5039 and examined
the configuration and the circumstellar environment of the system via radial
velocity measurements and detailed line-profile analysis of H-Balmer, He I and
He II lines.

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The categories of this paper are: math-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-bio
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The categories of this paper are: math
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The categories of this paper are: eess
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-ex
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The categories of this paper are: stat
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The categories of this paper are: chem-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ex