080407

The detection of jet-breaks in short GRBs afterglow light curves provided evidence that their emission is collimated. The knowledge of the jet opening angle openPartheta_jclosePar distribution of short GRBs is mandatory for a proper understanding of the true energetics and rate of this class of events. Only a handful of the short GRBs observed by Swift to date has a robust estimate of theta_j. We propose here to overcome this limit by carrying out ToO XMM-Newton observations of a sub-sample of Swift short GRBs openParselected maximizing the possibility of multi-wavelength follow-upclosePar comma hunting for a jet-break signature in their late-time X-ray afterglow light curves. The increasing evidence for compact object binary progenitors makes short GRBs one of the most promising sources of GWs.

对短伽马射线暴（short Gamma-Ray Bursts，GRBs）余辉光变曲线中喷流截断（jet-break）信号的探测，为其辐射具有准直性提供了观测证据。掌握短伽马射线暴的喷流张角θ_j分布特征，是准确理解这类事件的真实能量特性及其发生率的不可或缺的前提。截至目前，仅在少数被斯威夫特（Swift）望远镜观测到的短伽马射线暴中，得到了喷流张角θ_j的稳健估算结果。本研究拟通过以下方式突破这一局限：选取斯威夫特望远镜观测到的短伽马射线暴子样本，优先选择具备多波段后续观测潜力的目标，开展机会目标观测（Target of Opportunity，ToO）模式下的XMM-牛顿（XMM-Newton）望远镜观测，以搜寻其后期X射线余辉光变曲线中的喷流截断信号。越来越多的观测证据表明，短伽马射线暴的前身天体为致密双星系统，这使其成为最具潜力的引力波（Gravitational Waves，GWs）源之一。