Black Hole Mergers from Hierarchical Triples in Dense Star Clusters
Black Hole Mergers from Hierarchical Triples in Dense Star Clusters
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DOI：
10.3847/1538-4357/abba25
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发表时间：
2020-09
期刊：
影响因子：
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通讯作者：
Miguel A. S. Martinez;G. Fragione;K. Kremer;S. Chatterjee;C. Rodriguez;J. Samsing;Claire S. Ye
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文献类型：
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作者：
Miguel A. S. Martinez;G. Fragione;K. Kremer;S. Chatterjee;C. Rodriguez;J. Samsing;Claire S. Ye
球状星系团核心中频繁的二元调节相互作用有望产生层次化的三元组。在这些三元组中的一些中，由于偏心的Kozai-Lidov机制，第三伴星可以在大的偏心振荡之后驱动内双星合并。在这篇文章中，我们研究了黑洞(BH)等级三元组的动力学和合并率，这些三元组是在CMC星系团目录中通过双星-双星相遇形成的，CMC星系团目录是一套具有当今性质的星系团模拟，代表了银河系的球状星系团。我们比较了致密星团中三重合并和其他合并通道的性质，结果表明，三重合并在质量和有效自旋分布方面并没有产生显著的差异。然而，它们代表了形成偏心合并的重要途径，LIGO-Virgo/KAGRA(LVK)和未来的任务，如LISA和十赫干涉仪引力波天文台，都可以检测到这种合并。我们从本地宇宙中0.35gpc−3年−1的通道中得到了合并率的保守下限，并且在∼设计灵敏度下，这些事件中高达9%的事件可能具有可检测到的偏心。此外，我们发现三重系统可以在保留第二代BHS方面发挥重要作用，这些BHS稍后可以再次合并到主机集群的核心。
Hierarchical triples are expected to be produced by the frequent binary-mediated interactions in the cores of globular clusters. In some of these triples, the tertiary companion can drive the inner binary to merger following large eccentricity oscillations, as a result of the eccentric Kozai–Lidov mechanism. In this paper, we study the dynamics and merger rates of black hole (BH) hierarchical triples, formed via binary–binary encounters in the CMC Cluster Catalog, a suite of cluster simulations with present-day properties representative of the Milky Way’s globular clusters. We compare the properties of the mergers from triples to the other merger channels in dense star clusters, and show that triple systems do not produce significant differences in terms of mass and effective spin distribution. However, they represent an important pathway for forming eccentric mergers, which could be detected by LIGO–Virgo/KAGRA (LVK), and future missions such as LISA and the DECi-hertz Interferometer Gravitational wave Observatory. We derive a conservative lower limit for the merger rate from this channel of 0.35 Gpc−3 yr−1 in the local universe and up to ∼9% of these events may have a detectable eccentricity at LVK design sensitivity. Additionally, we find that triple systems could play an important role in retaining second-generation BHs, which can later merge again in the core of the host cluster.