Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence of Compton cooling during an X-ray flare supports a neutron
  star nature of the compact object in 4U1700-37   Based on new Chandra X-ray telescope data, we present empirical evidence of
plasma Compton cooling during a flare in the non pulsating massive X-ray binary
4U1700-37. This behaviour might be explained by quasispherical accretion onto a
slowly rotating magnetised neutron star. In quiescence, the neutron star in
4U1700-37 is surrounded by a hot radiatively cooling shell. Its presence is
supported by the detection of mHz quasi periodic oscillations likely produced
by its convection cells. The high plasma temperature and the relatively low
X-ray luminosity observed during the quiescence, point to a small emitting area
about 1 km, compatible with a hot spot on a NS surface. The sudden transition
from a radiative to a significantly more efficient Compton cooling regime
triggers an episode of enhanced accretion resulting in a flare. During the
flare, the plasma temperature drops quickly. The predicted luminosity for such
transitions, Lx = 3 x 10^35 erg s-1, is very close to the luminosity of
4U1700-37 during quiescence. The transition may be caused by the accretion of a
clump in the stellar wind of the donor star. Thus, a magnetised NS nature of
the compact object is strongly favoured.

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The categories of this paper are: physics
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The categories of this paper are: funct-an
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The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: math
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The categories of this paper are: hep-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-th
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The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: quant-ph