论文标题
二进制黑洞的合并速率密度在开放群集中形成
Merger rate density of binary black holes formed in open clusters
论文作者
论文摘要
使用重力波检测器观察到了几个二元黑洞（BBH）。对于BBH的形成机制，已经提出了两个主要机制，即孤立的二元演化和密集的星形簇中的动力学形成。预计未来的观察结果将提供有关BBH分布的更多信息，它将帮助我们区分两种形成机制。对于星簇通道，主要研究了球状簇。但是，最近的模拟表明，开放簇中的BBH形成不可忽略。我们估计BBHS的局部合并率密度是使用我们的$ N $ body-body仿真的开放式簇的结果，该群集的开放式群集具有四种不同的金属。我们发现，对于我们的0.1太阳金属度模型，每个集群的合并速率最高。假设宇宙星形的形成历史和随着分散体的金属性演变，我们估计BBHS的局部合并速率密度源自开放簇为$ \ sim 70〜 {\ rm yr}^{ - 1} { - 1} {\ rm GPC}^{ - 3} $。该值与Ligo和处女座的第一和第二观察过程中预期的合并速率密度相当。此外，我们发现从我们的模拟获得的BBH合并可以再现从Ligo和处女座观测值估计的合并BBH的原发质量和质量比的分布。
Several binary black holes (BBHs) have been observed using gravitational wave detectors. For the formation mechanism of BBHs, two main mechanisms, isolated binary evolution and dynamical formation in dense star clusters, have been suggested. Future observations are expected to provide more information about BBH distributions, and it will help us to distinguish the two formation mechanisms. For the star cluster channel, globular clusters have mainly been investigated. However, recent simulations have suggested that BBH formation in open clusters is not negligible. We estimate a local merger rate density of BBHs originated from open clusters using the results of our $N$-body simulations of open clusters with four different metallicities. We find that the merger rate per cluster is the highest for our 0.1 solar metallicity model. Assuming a cosmic star formation history and a metallicity evolution with dispersion, we estimate the local merger rate density of BBHs originated from open clusters to be $\sim 70~{\rm yr}^{-1} {\rm Gpc}^{-3}$. This value is comparable to the merger rate density expected from the first and second observation runs of LIGO and Virgo. In addition, we find that BBH mergers obtained from our simulations can reproduce the distribution of primary mass and mass ratio of merging BBHs estimated from the LIGO and Virgo observations.
