GW170817A as a Hierarchical Black Hole Merger
GW170817A as a Hierarchical Black Hole Merger
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DOI：
10.3847/2041-8213/ab745d
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发表时间：
2019-11
期刊：
影响因子：
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通讯作者：
V. Gayathri;I. Bartos;Z. Haiman;S. Klimenko;B. Kocsis;S. Márka;Y. Yang
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文献类型：
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作者：
V. Gayathri;I. Bartos;Z. Haiman;S. Klimenko;B. Kocsis;S. Márka;Y. Yang
尽管通过引力波发现的恒星质量双黑洞合并的数量迅速增加，但这些双星的起源仍然未知。在银河系中心，黑洞可以通过动力学过程彼此靠近，从而导致合并。也有可能是先前合并中形成的黑洞遇到了新的黑洞，从而产生了所谓的分层合并。分层事件具有诸如高于平常的黑洞质量和自旋等特征。在这里，我们表明最近报道的引力波候选者 GW170817A 可能是这种分层合并的结果。特别是，它的啁啾质量~40 M⊙和有效自旋χeff~0.5是活跃星系核盘内分层合并的典型预期值。我们发现 GW170817A 的重建参数强烈支持分层合并起源，而不是由孤立的二元起源（优势比 > 103）产生。
Despite the rapidly growing number of stellar-mass binary black hole mergers discovered through gravitational waves, the origin of these binaries is still not known. In galactic centers, black holes can be brought to each others’ proximity by dynamical processes, resulting in mergers. It is also possible that black holes formed in previous mergers encounter new black holes, resulting in so-called hierarchical mergers. Hierarchical events carry signatures such as higher-than-usual black hole mass and spin. Here we show that the recently reported gravitational-wave candidate, GW170817A, could be the result of such a hierarchical merger. In particular, its chirp mass ∼40 M⊙ and effective spin of χeff ∼ 0.5 are the typically expected values from hierarchical mergers within the disks of active galactic nuclei. We find that the reconstructed parameters of GW170817A strongly favor a hierarchical merger origin over having been produced by an isolated binary origin (with an odds ratio of > 103).