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arXiv 2104.06203astro-ph.HE
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盘控潮汐破裂事件的最大X射线光度标度

A maximum X-ray luminosity scale of disc-dominated tidal disruption events

Andrew Mummery

摘要:

我们开发了一个模型,描述了最低质量黑洞周围的盘主导的TDE的动力学和观测特性($M \lesssim {\rm few} \times 10^{6} M_\odot$)。质量最小的黑洞周围的TDE最有可能在演化的早期达到超爱丁顿光度。通过假设恒星碎片的数量,可以形成一个紧凑的吸积盘是动态设置的爱丁顿光度,我们做了一些有趣的和可检验的预测明亮的软态X射线TDEs和光学明亮,X射线暗淡的TDEs的观测特性。我们认为,最低质量的黑洞周围的TDE将驱逐绝大多数的引力束缚碎片进入辐射驱动的外流。一个大质量的外流将掩盖最里面的X射线产生区,导致人口的低黑洞质量的TDE,只有在光学\紫外能量观察。TDE盘的辐射热光度与其爱丁顿光度相当,其X射线光度接近恒定(即与黑洞质量无关),数量级为$L_{\rm X, max} \equiv L_M \sim 10^{43} - 10^{44}$ erg/s。光度值的范围主要来自于允许的黑洞自旋的范围。一个类似的X射线亮度极限存在于硬态(康普顿散射为主)的X射线TDEs,因此,我们预测,X射线亮度最亮的X射线TDEs将在$L_M(a) \sim 10^{43}-10^{44}$ erg/s的规模,独立于黑洞质量和吸积状态。这些预测与现有的人口($\sim 40$源)的观察到的TDE的属性是非常一致的。

英文摘要:

We develop a model describing the dynamical and observed properties of disc-dominated TDEs around black holes with the lowest masses ($M \lesssim {\rm few} \times 10^{6} M_\odot$). TDEs around black holes with the lowest masses are most likely to reach super-Eddington luminosities at early times in their evolution. By assuming that the amount of stellar debris which can form into a compact accretion disc is set dynamically by the Eddington luminosity, we make a number of interesting and testable predictions about the observed properties of bright soft-state X-ray TDEs and optically bright, X-ray dim TDEs. We argue that TDEs around black holes of the lowest masses will expel the vast majority of their gravitationally bound debris into a radiatively driven outflow. A large-mass outflow will obscure the innermost X-ray producing regions, leading to a population of low black hole mass TDEs which are only observed at optical \& UV energies. TDE discs evolving with bolometric luminosities comparable to their Eddington luminosity will have near constant (i.e. black hole mass independent) X-ray luminosities, of order $L_{\rm X, max} \equiv L_M \sim 10^{43} - 10^{44}$ erg/s. The range of luminosity values stems primarily from the range of allowed black hole spins. A similar X-ray luminosity limit exists for X-ray TDEs in the hard (Compton scattering dominated) state, and we therefore predict that the X-ray luminosity of the brightest X-ray TDEs will be at the scale $L_M(a) \sim 10^{43}-10^{44}$ erg/s, independent of black hole mass and accretion state. These predictions are in strong agreement with the properties of the existing population ($\sim 40$ sources) of observed TDEs.

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