Hard X-ray Luminosity Function of Tidal Disruption Events: First Results from MAXI Extragalactic Survey
Hard X-ray Luminosity Function of Tidal Disruption Events: First Results from MAXI Extragalactic Survey
复制标题
DOI：
10.1093/pasj/psw056
复制
发表时间：
2016-05
期刊：
影响因子：
--
通讯作者：
T. Kawamuro;Y. Ueda;M. Shidatsu;T. Hori;N. Kawai;H. Negoro;T. Mihara
中科院分区：
文献类型：
--
作者：
T. Kawamuro;Y. Ueda;M. Shidatsu;T. Hori;N. Kawai;H. Negoro;T. Mihara
利用全天空X射线图像监视器（MAXI）观测到的无偏样本，推导了超大质量黑洞（SMBH）引起的恒星潮汐破裂事件（TDEs）的第一硬X射线光度函数（XLF），给出了TDEs发生率与峰值光度和红移的函数关系.在光变曲线的基础上，其特征在于指数为$-5/3$的幂律衰减，在前37个月使用MAXI数据进行系统搜索，检测到四个TDE，所有这些都已在文献中找到。为了制定TDE XLF，我们考虑SMBH的质量函数，被破坏的恒星，特定的TDE率作为SMBH质量的函数，以及相对论性喷流的TDE分数。我们执行一个unbinned最大似然适合的MAXI TDE列表，并检查与ROSAT全天巡天观测TDE率的一致性。结果表明，喷流伴随事件的内禀分数为0.0007 - 34%.我们确认，在$z \lesssim 1.5$的污染由TDEs活动星系核的硬X射线光度函数是不显着的，因此，它们的增长的SMBHs的贡献是可以忽略不计的红移。
We derive the first hard X-ray luminosity function (XLF) of stellar tidal disruption events (TDEs) by supermassive black holes (SMBHs), which gives an occurrence rate of TDEs per unit volume as a function of peak luminosity and redshift, utilizing an unbiased sample observed by the Monitor of All-sky X-ray Image (MAXI). On the basis of the light curves characterized by a power-law decay with an index of $-5/3$, a systematic search using the MAXI data in the first 37 months detected four TDEs, all of which have been found in the literature. To formulate the TDE XLF, we consider the mass function of SMBHs, that of disrupted stars, the specific TDE rate as a function of SMBH mass, and the fraction of TDEs with relativistic jets. We perform an unbinned maximum likelihood fit to the MAXI TDE list and check the consistency with the observed TDE rate in the ROSAT all sky survey. The results suggest that the intrinsic fraction of the jet-accompanying events is $0.0007$--$34\%$. We confirm that at $z \lesssim 1.5$ the contamination by TDEs to the hard X-ray luminosity functions of active galactic nuclei is not significant and hence that their contribution to the growth of SMBHs is negligible at the redshifts.