Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hard X-ray flares in IGR J08408-4503 unveil clumpy stellar winds   Context : A 1000-s flare from a new hard X-ray transient, IGR J08408-4503,
was observed by INTEGRAL on May 15, 2006 during the real-time routine
monitoring of IBIS/ISGRI images performed at the INTEGRAL Science Data Centre.
The flare, detected during a single one-hour long pointing, peaked at 250 mCrab
in the 20-40 keV energy range.
  Aims : Multi-wavelength observations, combining high-energy and optical data,
were used to unveil the nature of IGR J08408-4503.
  Methods : A search in all INTEGRAL public data for other bursts from IGR
J08408-4503 was performed, and the detailed analysis of another major flare is
presented. The results of two Swift Target of Opportunity observations are also
described. Finally, a study of the likely optical counterpart, HD 74194, is
provided.
  Results : IGR J08408-4503 is very likely a supergiant fast X-ray transient
(SFXT) system. The system parameters indicate that the X-ray flares are
probably related to the accretion of wind clumps on a compact object orbiting
about 1E13 cm from the supergiant HD 74194. The clump mass loss rate is of the
order of 1E-6 solar mass/yr.
  Conclusions : Hard X-ray flares from SFXTs allow to probe the stellar winds
of massive stars, and could possibly be associated with wind perturbations due
to line-driven instabilities.

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The categories of this paper are: hep-ex
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The categories of this paper are: q-alg
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The categories of this paper are: solv-int
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The categories of this paper are: cs
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The categories of this paper are: eess
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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-th
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ph
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The categories of this paper are: math-ph
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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: supr-con
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The categories of this paper are: physics
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The categories of this paper are: gr-qc