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arXiv 1901.05063astro-ph.GA
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富双星星团中的中等质量黑洞

Intermediate-Mass Black Holes in binary-rich star clusters

L. Subr, G. Fragione, J. Dabringhausen

摘要:

无论是理论上的期望还是观测上的线索都表明中等质量黑洞存在于球状星团的核中。为了找到一个独立的指标,他们的存在,我们在本文中调查如何IMBH表现出自己通过其动力学相互作用与二进制丰富的球状星团的适度扩展和质量。通过直接的$N$ -体集成,我们遵循这样一个系统的模型的动力学演化的时间跨度为$\approx$ 0.8 Gyr和比较的情况下,有和没有原始的双星,以及有和没有IMBH。在符合以前的结果,我们表明,当本IMBH开发一个幂律密度尖点的恒星周围,无论在集群中的二进制人口。然而,如果双星存在,它们与IMBH的相互作用会导致产生高速逃逸星,其速度约为100万年$^{-1}$。这些恒星可能有助于在银河系中观察到的高速恒星的人口。拥有IMBH和大量双星的星团也比缺乏IMBH或丰富双星的星团形成了更密集的边缘未束缚恒星晕。最后,我们表明,二进制人口导致增加率的直接相互作用的恒星与IMBH,可能观察到的潮汐中断事件。

英文摘要:

There is both theoretical expectation and some observational clues that intermediate mass black holes reside in nuclei of globular clusters. In order to find an independent indicator for their existence, we investigate in this paper how an IMBH manifests itself through its dynamical interaction with a binary rich globular cluster of moderate extension and mass. By means of direct $N$-body integration we follow the dynamical evolution of models of such a system over a time span of $\approx$ 0.8 Gyr and compare the cases with and without the primordial binaries as well as with and without the IMBH. In accord with previous results, we show that when present the IMBH develops a power-law density cusp of stars around it, regardless of the binary population in the cluster. If, however, binaries are present, their interaction with the IMBH leads to the production of high velocity escapers at a rate of the order of 0.1 Myr$^{-1}$. These stars may contribute to the population of high-velocity stars observed in the Galaxy. Clusters hosting the IMBH together with high number of binaries also form a denser halo of marginally unbound stars than clusters that lack either the IMBH or the rich binary population. Finally, we show that the binary population leads to an increased rate of direct interactions of stars with the IMBH, potentially observable as tidal disruption events.

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