DETECTION OF NON-THERMAL X-RAY EMISSION FROM GAMMA2 VELORUM

Our NuSTAR observations of two massive colliding wind binary systems presentedclear evidence of highenergy, nonthermal emission, which probably originatefrom inverseCompton (IC) of stellar photons by highenergy electronsaccelerated at the windwind colliding (WWC) shocks. However, the observedemission is nearly constant unlike the WWC thermal emission, and this is notexpected from the standard IC mechanism. To understand the emission mechanism,we need more colliding wind binary systems with different stellar parameters. Wepropose two NuSTAR observations of another colliding wind binary system, gamma2Velorum, whichshows signatures of WWC Xray activity and has a GeV gammaray counterpart, to detect highenergy nonthermal emission. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]