Stellar-mass black holes in young massive and open stellar clusters and their role in gravitational-wave generation
Stellar-mass black holes in young massive and open stellar clusters and their role in gravitational-wave generation
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DOI：
10.1093/mnras/stw3392
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发表时间：
2016-11
影响因子：
4.8
通讯作者：
S. Banerjee
中科院分区：
文献类型：
--
作者：
S. Banerjee
密集星团中恒星残骸黑洞（BH）的研究现在处于聚光灯下，特别是由于它们通过动态相遇形成双黑洞（BBH）的内在能力，这种能力可能通过引力波（GW）辐射合并。在这项工作中，这是最近一项研究的延续（论文1），具有初始质量$\lesssim10^5M_\odot$的致密恒星团的附加模型以及具有原始双星的一小部分的模型($\lesssim10$%) are evolved for long term, applying the direct N-body approach, assuming state-of-the-art stellar-wind and remnant-formation prescriptions. That way, a substantially broader range of computed models than that in Paper I is achieved. As in Paper I, the general-relativistic BBH mergers continue to be mostly mediated by triples that are bound to the clusters rather than happen among the ejected BBHs. In fact, the number of such in situ BBH mergers, per cluster, tend to increase significantly with the introduction of a small population of primordial binaries. Despite the presence of massive primordial binaries, the merging BBHs, especially the in situ ones, are found to be exclusively dynamically assembled and hence would be spin-orbit misaligned. The BBHs typically traverse through both the LISA's and the LIGO's detection bands, being audible to both instruments. The "dynamical heating" of the BHs keeps the Electron-Capture-Supernova (ECS) neutron stars (NS) from effectively mass segregating and participating in exchange interactions; the dynamically-active BHs would also exchange into any NS binary within $\lesssim1$ Gyr. Such young massive and open clusters have the potential to contribute to the dynamical BBH merger detection rate to a similar extent as their more massive globular-cluster counterparts.
The study of stellar-remnant black holes (BH) in dense stellar clusters is now in the spotlight, especially due to their intrinsic ability to form binary black holes (BBH) through dynamical encounters, that potentially coalesce via gravitational-wave (GW) radiation. In this work, which is a continuation of a recent study (Paper I), additional models of compact stellar clusters with initial masses $\lesssim10^5M_\odot$ and also those with small fractions of primordial binaries ($\lesssim10$%) are evolved for long term, applying the direct N-body approach, assuming state-of-the-art stellar-wind and remnant-formation prescriptions. That way, a substantially broader range of computed models than that in Paper I is achieved. As in Paper I, the general-relativistic BBH mergers continue to be mostly mediated by triples that are bound to the clusters rather than happen among the ejected BBHs. In fact, the number of such in situ BBH mergers, per cluster, tend to increase significantly with the introduction of a small population of primordial binaries. Despite the presence of massive primordial binaries, the merging BBHs, especially the in situ ones, are found to be exclusively dynamically assembled and hence would be spin-orbit misaligned. The BBHs typically traverse through both the LISA's and the LIGO's detection bands, being audible to both instruments. The "dynamical heating" of the BHs keeps the Electron-Capture-Supernova (ECS) neutron stars (NS) from effectively mass segregating and participating in exchange interactions; the dynamically-active BHs would also exchange into any NS binary within $\lesssim1$ Gyr. Such young massive and open clusters have the potential to contribute to the dynamical BBH merger detection rate to a similar extent as their more massive globular-cluster counterparts.