Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The complex Halpha line profile of the bright companion to PSR
  J1740-5340 in NGC 6397   We present a detailed study of the Halpha and He I spectral features of COM
J1740-5340 (the companion to PSR J1740-5340 in the Galactic Globular Cluster
NGC 6397), exploiting a series of high resolution spectra obtained at different
orbital phases. The Halpha absorption line shows a complex two-component
structure, revealing that optically thin hydrogen gas resides outside the Roche
lobe of COM J1740-5340. The line morphology precludes the existence of any
residual disk around the millisecond pulsar, and suggests the presence of a
stream of material going from the companion toward the neutron star. This
material never reaches the neutron star surface, being driven back by the
pulsar radiation far beyond COM J1740-5340. By analyzing the He I absorption
lines as a function of orbital phase, we infer the presence of an overheated
longitudinal strip (about 150 times narrower than it is long) on the COM
J1740-5340 surface facing the radio pulsar.

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The categories of this paper are: cond-mat
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ph
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The categories of this paper are: physics
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The categories of this paper are: hep-th
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The categories of this paper are: quant-ph
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-th
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The categories of this paper are: atom-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: bayes-an
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The categories of this paper are: ao-sci
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The categories of this paper are: chem-ph
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The categories of this paper are: funct-an
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The categories of this paper are: adap-org
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The categories of this paper are: cmp-lg