On the Origin of GW190521-like Events from Repeated Black Hole Mergers in Star Clusters
On the Origin of GW190521-like Events from Repeated Black Hole Mergers in Star Clusters
复制标题
DOI：
10.3847/2041-8213/abbc0a
复制
发表时间：
2020-09
期刊：
影响因子：
--
通讯作者：
G. Fragione;A. Loeb;F. Rasio
中科院分区：
文献类型：
--
作者：
G. Fragione;A. Loeb;F. Rasio
LIGO和Virgo报告了GW 190521的发现，它来自一个总质量约为150 M的双黑洞（BBH）的合并。虽然目前的恒星模型将任何黑洞（BH）残余物的质量限制在40-50 M，但在致密星星的核心，通过重复合并可以动态地产生更大质量的BH。这个过程受到反冲反冲（由于引力辐射的各向异性发射）的限制，这些反冲被赋予合并残余物，这些残余物可以逃离母星系团，从而终止增长。我们研究了主集群的金属丰度和逃逸速度的积累大规模BH通过重复合并的作用。几乎独立于主金属丰度，我们发现，大约150 M的BBH可以动态地形成在任何星星集群与逃逸速度超过200 km s-1，在银河系的核星星集群以及最大质量的球状星团和超级星星集群。使用仅含吸气的波形，我们计算了不同初始质量（≥60 M Ω）的探测概率随次级质量的变化，发现探测概率随次级质量的增加而增加，随初始质量和红移的增大而减小。未来更多的大规模BBH合并的检测将是根本的重要性，了解大规模BH的增长，通过动力学和中等质量BH的形成。
LIGO and Virgo have reported the detection of GW190521, from the merger of a binary black hole (BBH) with a total mass around 150 M⊙. While current stellar models limit the mass of any black hole (BH) remnant to about 40–50 M⊙, more massive BHs can be produced dynamically through repeated mergers in the core of a dense star cluster. The process is limited by the recoil kick (due to anisotropic emission of gravitational radiation) imparted to merger remnants, which can escape the parent cluster, thereby terminating growth. We study the role of the host cluster metallicity and escape speed in the buildup of massive BHs through repeated mergers. Almost independent of host metallicity, we find that a BBH of about 150 M⊙ could be formed dynamically in any star cluster with escape speed ≳200 km s−1, as found in galactic nuclear star clusters as well as the most massive globular clusters and super star clusters. Using an inspiral-only waveform, we compute the detection probability for different primary masses (≥60 M⊙) as a function of secondary mass and find that the detection probability increases with secondary mass and decreases for larger primary mass and redshift. Future additional detections of massive BBH mergers will be of fundamental importance for understanding the growth of massive BHs through dynamics and the formation of intermediate-mass BHs.