On the Likely Dynamical Origin of GW191109 and Binary Black Hole Mergers with Negative Effective Spin
On the Likely Dynamical Origin of GW191109 and Binary Black Hole Mergers with Negative Effective Spin
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DOI：
10.3847/1538-4357/ace4c1
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发表时间：
2023-02
期刊：
影响因子：
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通讯作者：
Rachel C. Zhang;G. Fragione;Chase Kimball;V. Kalogera
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文献类型：
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作者：
Rachel C. Zhang;G. Fragione;Chase Kimball;V. Kalogera
随着LIGO/Virgo/KAGRA探测到的双星黑洞(BBH)合并的数量越来越多，一些系统已经变得难以用孤立的双星演化来解释，这些系统中的组件包括不稳定的质量间隙、高度的轨道偏心率和/或自旋-轨道错位。这里我们关注的是GW191109_010717，它的成分质量为65−11+11和47−13+15M⊙，有效自旋为−0.29−0.31+0.42，这可能意味着它的至少一个成分的自旋-轨道错位超过π/2rad。除了它的分量质量处于对不稳定质量间隙之外，我们还表明孤立的双星演化不太可能高置信度地重现所提出的GW191109的自旋轨道失准。另一方面，我们证明了在密集星团中动态组装的BBH将自然地重现GW191109的自旋-轨道错位和质量以及GW191109类事件的速率，如果其中至少有一个是第二代BH的话。最后，我们将我们的结果推广到所有具有测量的负有效自旋的事件，认为GW200225也可能有一个动力学起源。
With the growing number of binary black hole (BBH) mergers detected by LIGO/Virgo/KAGRA, several systems have become difficult to explain via isolated binary evolution, having components in the pair-instability mass gap, high orbital eccentricities, and/or spin–orbit misalignment. Here we focus on GW191109_010717, a BBH merger with component masses of 65−11+11 and 47−13+15 M ⊙ and an effective spin of −0.29−0.31+0.42 , which could imply a spin–orbit misalignment of more than π/2 rad for at least one of its components. Besides its component masses being in the pair-instability mass gap, we show that isolated binary evolution is unlikely to reproduce the proposed spin–orbit misalignment of GW191109 with high confidence. On the other hand, we demonstrate that BBHs dynamically assembled in dense star clusters would naturally reproduce the spin–orbit misalignment and masses of GW191109 and the rates of GW191109-like events if at least one of the components were to be a second-generation BH. Finally, we generalize our results to all events with a measured negative effective spin, arguing that GW200225 also has a likely dynamical origin.