2007A&A...465L..35L -
Astronomy and Astrophysics, volume 465, L35-38 (2007/4-3)
Hard X-ray flares in IGR J08408-4503 unveil clumpy stellar winds.
LEYDER J.-C., WALTER R., LAZOS M., MASETTI N. and PRODUIT N.
Abstract (from CDS):
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 20-40keV energy range. Multi-wavelength observations, combining high-energy and optical data, were used to unveil the nature of
IGR J08408-4503. 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.
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 10
13cm from the supergiant
HD 74194. The clump mass loss rate is of the order of 10
–6M
☉/yr. 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.
Abstract Copyright:
∼
Journal keyword(s):
gamma rays: observations - stars: supergiants - X-rays: individuals: IGR J08408-4503
Simbad objects:
2
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