IGR J08408–4503: A New Recurrent Supergiant Fast X-Ray Transient

• Published in: The Astrophysical journal 2007-02, Vol.655 (2), p.L101-L104
• Main Authors: Götz, D, Falanga, M, Senziani, F, De Luca, A, Schanne, S, von Kienlin, A
• Format: Article
• Language: English
• Subjects: Astronomy; Astrophysics; Cosmology and Extra-Galactic Astrophysics; Earth, ocean, space; Exact sciences and technology; Physics; Sciences of the Universe
• ISSN: 1538-4357; 0004-637X; 1538-4357
• DOI: 10.1086/511818

The supergiant fast X-ray transient IGR J08408-4503 was discovered by INTEGRAL on 2006 May 15 during a bright flare. The source shows sporadic recurrent short bright flares, reaching a peak luminosity of 10 super(36) ergs s super(-1) within less than 1 hr. The companion star is HD 74194, an Ob5Ib(f) supergiant star located at 3 kpc in the Vela region. We report the light curves and broadband spectra (0.1-200 keV) of all the three flares of IGR J08408-4503 detected up to now, based on INTEGRAL and Swift data. The flare spectra are well described by a power-law model with a high-energy cutoff at 615 keV. The absorption column density during the flares was found to be 610 super(21) cm super(-2), indicating a very low matter density around the compact object. Using the supergiant donor star parameters, the wind accretion conditions imply an orbital period of the order of 1 yr, a spin period of the order of hours, and a magnetic field of the order of 10 super(13) G.