arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2108.05593astro-ph.HEastro-ph.GA
收藏

喷流TDE雨燕J1644 +57短周期X射线光变的长期演化

Long-term Evolution of the Short-term X-ray Variability of the Jetted TDE Swift J1644+57

Chichuan Jin

摘要:

潮汐破裂事件(TDEs)的短期X射线变率及其与活动星系核(AGN)的相似性知之甚少。本文展示了TDE短期X射线光变的多样性,并以Swift J1644+57为例,研究了与TDE短期X射线光变相关的各种性质的演化,如X射线通量分布、功率谱密度(PSD)、均方根光变、时间滞后和相干谱等。结果表明,Swift J1644+57在正常态下的通量分布为对数正态分布,而在倾斜态下的通量分布明显偏离对数正态分布,这说明两种态下的物理机制不同.我们还发现,在前两个XMM-牛顿观测在浸渍状态下,斯威夫特J1644+57表现出不同的变化模式,其特点是更陡峭的PSD和更大的均方根比正常状态。在这两个观测中检测到显著的软X射线滞后,其在0.3-1 keV和2-10 keV之间约为50 s,具有高相干性。使用2-10 keV的均方根值为0.10-0.50,斯威夫特J1644+57的黑洞质量估计为$(0.6-7.9)\times10^{6}M_{\odot}$,但均方根值的变化,随着TDE的演变引入了很大的不确定性。最后,我们讨论了对其他TDEs进行类似研究的价值,特别是在即将到来的时域天文学时代,当更多的TDEs将被发现在X射线迅速。这也预示着对利用有效面积大、轨道周期长的X射线望远镜对某些X射线TDEs进行深度跟踪观测的需求将大大增加。

英文摘要:

The short-term X-ray variability of tidal disruption events (TDEs) and its similarities with active galactic nuclei (AGN) are poorly understood. In this work, we show the diversity of TDE's short-term X-ray variability, and take Swift J1644+57 as an example to study the evolution of various properties related to the short-term X-ray variability, such as the X-ray flux distribution, power spectral density (PSD), rms variability, time lag and coherence spectra. We find that the flux distribution of Swift J1644+57 has a lognormal form in the normal state, but deviates from it significantly in the dipping state, thereby implying different physical mechanisms in the two states. We also find that during the first two XMM-Newton observations in the dipping state, Swift J1644+57 exhibited different variability patterns, which are characterized by steeper PSDs and larger rms than the normal state. A significant soft X-ray lag is detected in these two observations, which is ~50 s between 0.3-1 keV and 2-10 keV with a high coherence. Using the 2-10 keV rms of 0.10-0.50, the black hole mass of Swift J1644+57 is estimated to be $(0.6-7.9)\times10^{6}M_{\odot}$, but the variation of rms as the TDE evolves introduces a large uncertainty. Finally, we discuss the value of conducting similar studies on other TDEs, especially in the coming era of time-domain astronomy when a lot more TDEs will be discovered in X-rays promptly. This also heralds a significant increase in the demand for deep follow-up observations of X-ray selected TDEs with X-ray telescopes of large effective areas and long orbital periods.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑