Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: X-ray observations of the peculiar Be star LSI +61 303   We present the results of a ROSAT Position Sensitive Proportional Counter
observation of the variable radio star \ls. The source has a power law spectrum
with photon index 1.1 +/- 0.3 and a luminosity of 5.9 x 10^{33} erg/s in the
0.1 -2.4 keV range. Variability on a timescale of days is clearly visible in
the ROSAT data, but no periodic pulsations have been detected. The low X--ray
luminosity is difficult to explain in the context of the models involving super
Eddington accretion which have been proposed to account for the non thermal
radio outbursts. Though the weak X--ray flux is marginally compatible with the
levels expected from normal B and Be star winds, the variability and the rather
hard spectrum are more suggestive of non thermal emission. This might originate
in a shocked region produced by a young pulsar in orbit around the Be star.

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The categories of this paper are: dg-ga
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The categories of this paper are: cond-mat
30
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: comp-gas
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The categories of this paper are: acc-phys
3
The categories of this paper are: physics
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The categories of this paper are: econ
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The categories of this paper are: q-fin
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The categories of this paper are: solv-int
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The categories of this paper are: q-bio
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The categories of this paper are: cs
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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: nucl-th
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The categories of this paper are: supr-con