243 articles – 3617 Notices  [english version]
 HAL : in2p3-00086591, version 1
 arXiv : astro-ph/0404097
 5th INTEGRAL Workshop, Munich : Allemagne
 High-energy emission from the stellar wind collisions in gamma-2 Velorum
 (2004)
 The binary system gamma-2 Velorum (WC8+O7.5) contains the nearest known Wolf-Rayet star to the Sun, at a distance of 258$_{-31}^{+41}$ pc. Its strong radio emission shows evidence for a partially absorbed nonthermal component, which has been interpreted as synchrotron emission from electrons accelerated in the colliding wind region. Inverse Compton cooling of these electrons in the intense UV radiation field from the O-type companion star could produce a significant hard X-ray and gamma-ray emission, whose flux depends on the ratio of the energy densities of magnetic to seed photon fields. The Vela region was observed with the INTEGRAL satellite in 2003, as part of the Core Programme. No signals from gamma-2 Vel are detected in the images obtained with the IBIS/ISGRI coded aperture instrument in the energy ranges 20-40 and 40-80 keV. From the derived 3$\sigma$ upper limits, we show that the average magnetic field near the region of stellar wind collision should be relatively high, greater than about 1 G. The high-energy emission of gamma-2 Vel might be detected with the forthcoming GLAST experiment.
 Thème(s) : Physique/Astrophysique/Cosmologie et astrophysique extra-galactiquePlanète et Univers/Astrophysique
 Lien vers le texte intégral : http://fr.arXiv.org/abs/astro-ph/0404097
 in2p3-00086591, version 1 http://hal.in2p3.fr/in2p3-00086591 oai:hal.in2p3.fr:in2p3-00086591 Contributeur : Dominique Girod <> Soumis le : Mercredi 19 Juillet 2006, 11:13:23 Dernière modification le : Mercredi 19 Juillet 2006, 11:14:54