X-ray investigation of the first gamma-ray emitter associated with a WR star

A systematic search for hard Xray and soft gammaray emission from WolfRayet(WR) stars, performed using the ISGRI imager, led to the detection of WR 115(2651 keV). This highenergy emission is expected to be produced by nonthermalrelativistic particles, through several possible mechanisms. However, it isstill unknown which of these proposed mechanisms is responsible for the observedemission, and whether the corresponding Xray emission is of a thermal ornonthermal origin. Therefore, we propose to observe this first gammarayemitter associated with a WR+O system. These observations of WR 115 withXMMNewton will help to confirm the origin of the emission seen at higherenergies, and to pinpoint the emission mechanisms thanks to a thorough analysis of its Xray spectrum. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]