Partial tidal disruption events by stellar mass black holes: Gravitational instability of stream and impact from remnant core
Partial tidal disruption events by stellar mass black holes: Gravitational instability of stream and impact from remnant core
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DOI：
10.1093/mnras/stab802
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发表时间：
2021-03
期刊：
影响因子：
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通讯作者：
Yihan Wang;R. Perna;P. Armitage
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文献类型：
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作者：
Yihan Wang;R. Perna;P. Armitage
在致密的星星团中，例如球状星团和疏散星团，恒星和黑洞（BH）之间的动力学相互作用可能极其频繁，导致各种天体物理瞬变。一颗星星和一颗恒星质量BH的近距离相遇，使得这颗星星有可能被BH潮汐扰动。由于BH的质量相对较低，并且对于具有高穿透力的情况，潮汐扰动事件（TDE）的横截面较小，因此由近距离相遇引起的扰动通常是部分扰动。残余恒星核心的存在及其与恒星质量BH相比不可忽略的质量显著改变了吸积过程。我们研究这个问题与SPH模拟使用的代码幻影，包括辐射压力，这是很重要的小质量BH。此外，我们开发了一种新的，更一般的方法计算回退率，不依赖于任何近似。我们的研究表明，幂律斜率的回落率有很强的依赖于BH的质量在恒星质量BH政权。此外，在这种制度下，自重力的回落流和局部不稳定性变得更加显着，并导致破碎的材料崩溃成小块，然后返回到BH。这导致回退率的突然增加，这可能显著偏离幂律。我们的研究结果将有助于识别TDE的恒星质量BH在密集的集群。
In dense star clusters, such as globular and open clusters, dynamical interactions between stars and black holes (BHs) can be extremely frequent, leading to various astrophysical transients. Close encounters between a star and a stellar mass BH make it possible for the star to be tidally disrupted by the BH. Due to the relative low mass of the BH and the small cross section of the tidal disruption event (TDE) for cases with high penetration, disruptions caused by close encounters are usually partial disruptions. The existence of the remnant stellar core and its non-negligible mass compared to the stellar mass BH alters the accretion process significantly. We study this problem with SPH simulations using the code Phantom, with the inclusion of radiation pressure, which is important for small mass BHs. Additionally, we develop a new, more general method of computing the fallback rate which does not rely on any approximation. Our study shows that the powerlaw slope of the fallback rate has a strong dependence on the mass of the BH in the stellar mass BH regime. Furthermore, in this regime, self-gravity of the fallback stream and local instabilities become more significant, and cause the disrupted material to collapse into small clumps before returning to the BH. This results in an abrupt increase of the fallback rate, which can significantly deviate from a powerlaw. Our results will help in the identification of TDEs by stellar mass BHs in dense clusters.