论文标题
年轻大型和开放式恒星簇V中的恒星质量黑洞V：与Ligo-Virgo合并率密度的比较
Stellar-mass black holes in young massive and open stellar clusters V: comparisons with LIGO-Virgo merger rate densities
论文作者
论文摘要
我研究了年轻的大型星形簇（YMC）和开放型星团（OCS）对当今动态组装二进制黑洞（BBHS）的固有合并速率密度的贡献。 BBH合并事件速率是根据Banerjee（2021）中提出的一组65个星形簇的最先进的进化模型估算的。这些相对论的直接多体计算的模型结合了最新的恒星质量损失和残留的形成成分。根据观测值，根据群集的质量分布和宇宙恒星的形成和富集历史，通过在模型中构建宇宙的簇种群来获得合并率。 BBH合并率密度的型号范围从悲观到$ 0.5 {\ rm〜 yr}^{ - 1} {\ rm GPC}^{ - 3}^{ - 3} -37.9 {\ rm〜yr}检测器范围。参考率很好地适应了从GWTC-1和GWTC-2合并事件目录中估计的BBH合并率密度。计算出的模型还产生了差异性BBH合并率密度，这些密度与GWTC-1和GWTC-2的限制性更大的差异合理一致。这些结果表明，原则上，YMC和OC中的动态相互作用可以解释BBH合并速率密度及其对合并二进制特性的依赖性，这是从迄今重力波（GW）事件中推断出的。还研究了合并速率密度的宇宙演化。这些模型预测$ \ oft5 {\ rm〜 yr}^{ - 1} {\ rm gpc}^{ - 3} $的速率用于YMCS和OCS的偏心Ligo-Virgo合并。通过安装GW事件，对BBH合并率密度的改进限制将有助于约束跨宇宙时间的星团形成的场景，以及各种紧凑型二进制合并通道的相对贡献。
I study the contribution of young massive star clusters (YMCs) and open star clusters (OCs) to the present-day intrinsic merger rate density of dynamically-assembled binary black holes (BBHs). The BBH merger event rate is estimated based on a set of 65 state-of-the-art evolutionary models of star clusters, as presented in Banerjee (2021). These relativistic direct many-body computed models incorporate up-to-date stellar mass loss and remnant formation ingredients. The merger-event rates are obtained by constructing a cluster population of the Universe, out of the models, taking into account mass distribution of clusters and cosmic star formation and enrichment histories, as per observations. The model BBH merger rate density ranges from a pessimistic to a reference value of $0.5{\rm~yr}^{-1}{\rm Gpc}^{-3}-37.9{\rm~yr}^{-1}{\rm Gpc}^{-3}$, for a LIGO-Virgo-like detector horizon. The reference rate well accommodates the BBH merger rate densities estimated from GWTC-1 and GWTC-2 merger-event catalogues. The computed models also yield differential BBH merger rate densities that agree reasonably with those from GWTC-1 and, as well, with the much more constrained ones from GWTC-2. These results suggest that dynamical interactions in YMCs and OCs can, in principle, alone explain the BBH merger rate density and its dependence on the merging-binary properties, as inferred from to-date gravitational-wave (GW) events. The cosmic evolution of merger rate density from the computed models is also studied. The models predict a rate of $\approx5{\rm~yr}^{-1}{\rm Gpc}^{-3}$ for eccentric LIGO-Virgo mergers from YMCs and OCs. The improving constraints on BBH merger rate density with mounting GW events will help constraining scenarios of star cluster formation across cosmic time and as well the relative contributions of the various compact binary merger channels.
