爱因斯坦探针卫星的核塌缩超新星激波暴探测  

On the detection of shock breakouts of core-collapse supernovae with the Einstein Probe satellite

作　　者：邓劲松[1,2] 王祥玉 

机构地区：[1]中国科学院国家天文台空间科学与技术重点实验室,北京100012 [2]中国科学院大学天文与空间科学学院,北京100049 [3]南京大学天文与空间科学学院,南京210093

出　　处：《中国科学：物理学、力学、天文学》2018年第3期55-62,共8页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：中国科学院战略性先导科技专项(编号:XDA15052100)资助

摘　　要：在核塌缩超新星爆发过程中,当辐射主导的爆炸激波传播到前身星表面附近时,高温辐射逃逸形成激波暴,是超新星最早的电磁信号.激波暴热辐射以紫外和软X射线光子为主,持续时间短暂(~10–1000 s),仅有几个疑似观测事例.爱因斯坦探针卫星开展的大视场、高灵敏度的软X射线快速全天巡天,预期每年将获得几十颗II-P型超新星的激波暴光变曲线,对蓝超巨星爆发和Ib/Ic型超新星的激波暴合计也可能有一到数颗的年探测率,有望用于限制前身星类型、爆前物质损失、超新星爆发机制等.The shock breakout process and its characteristics for various core-collapse supernovae types are described, after a brief introduction of main observational facts and theoretical hypotheses of core-collapse supernovae. A radiation-dominated shock is formed and transports outwards inside the progenitor star during a core-collapse-induced explosion, while the high-temperature radiation field is trapped behind the shock front that has a finite width corresponding to an optical depth of about 10-20. When the shock reaches close to the progenitor surface, the trapped radiation begins to leak out, mainly in the form of ultraviolet and soft X-ray photons, giving rise to a sudden huge brightening of the star which must be the first electromagnetic signal of a core-collapse supernova. The dttration of a shock breakout is very short, ranging from about 10 s for the explosion of a compact Wolf-Rayet star to about 1000 s for that of an extended red supergiant. Because of this, only few questionable candidates have been discovered so far including a serendipitous detection of SN 2008D with an X-ray telescope onboard the Swift satellite. The Einstein Probe satellite will run an all-sky survey of high sensitivity and high cadence in the soft X-ray band with its wide-field telescope of a Lobster-eye type, which is very suitable for the detection of ephemeral supernova shock breakouts. Using some typical theoretical values of shock breakouts, including durations, spectrum temperatures, and peak luminosities, it is predicted that each year the satellite will be able to routinely obtain dozens of light curves of shock breakouts for type II-P supernovae, i.e., explosions of red supergiants. But the rate drops to less than few detections per year for the explosions of blue supergiants and those of Wolf-Rayet stars in total due to compactness of such stars. The shock breakout sample to be built by the Einstein Probe satellite can be used to constrain the progenitors, in particular their radii, pre-explosion mass losses, and explosion

关 键 词：超新星 激波 X射线源 X射线望远镜 

分 类 号：P145.3[天文地球—天体物理]