时间：27日上午10：00

　　地点：报告厅4楼会议室

　　报告人:张国宝 博士

　　主持人：屈进禄 研究员

　　题目：Two bright minioutbursts end the 12-year long activity of the black hole candidate Swift J1753.5-0127

　　摘要：We present optical, UV and X-ray monitoring of the short orbital period black hole {\bf X-ray binary} candidate \src, focusing on the final stages of its 12-year long outburst that started in 2005. After the outburst peak, the optical flux has remained relatively steady, well above pre-outburst levels. From September 2016 onward, the source started to fade and within three months, the optical flux almost reached the quiescent level. Soon after that, we recorded two minioutbursts peaking in February (V~ 16.9) and May (V~ 17.9) 2017. Remarkably, the first has a peak flux consistent with the extrapolation of the slow decay before the fading phase preceding it. The second minioutburst is fainter and shorter. We found from optical colors that the temperature of the outer disk was ~ 11,000 K when the source started to fade rapidly. According to the disk instability model, this is close to the critical temperature when a cooling wave is expected to form in the disk, shutting down the outburst. The optical color could be a useful tool to predict decay rates in some X-ray transients. Other X-ray binaries that have known minioutbursts following an outburst are all short orbital period systems (< 7 h). In analogy with another class of short period binaries showing similar minioutbursts, the cataclysmic variables of the RZ LMi type, we suggest minioutbursts could occur if there is a hot inner disk at the end of the outburst decay.

　　个人简介：

　　张国宝博士：2008年获格林尼根大学博士学位，此后在格林尼根大学和纽约大学阿布扎比分校博士后。主要方向是X射线致密天体的观测研究。