A Dynamical Survey of Stellar-mass Black Holes in 50 Milky Way Globular Clusters
A Dynamical Survey of Stellar-mass Black Holes in 50 Milky Way Globular Clusters
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DOI：
10.3847/1538-4357/ab9f98
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发表时间：
2019-11
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影响因子：
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通讯作者：
Newlin C. Weatherford;S. Chatterjee;K. Kremer;F. Rasio
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作者：
Newlin C. Weatherford;S. Chatterjee;K. Kremer;F. Rasio
最近对球状星团（GC）的数值模拟表明，恒星质量黑洞（BH）在驱动星团演化和塑造其现今结构方面发挥着重要作用。黑洞的质量迅速地向GC中心分离，通过反复的超弹性散射作为动力学能源，延迟了核心坍缩的开始，并限制了可见星的质量分离。虽然最近在银河系和河外GC中发现的BH候选人进一步激起了人们对BH介导的星系团动力学的兴趣，但数值模型表明，即使在今天的GC中仍然存在大量BH，它们通常也不会处于直接可检测的配置中。我们在Weatherford等人的研究中证明，在GC模型中，可观测到的恒星群体中的质量分离（Δ）与保留的BH数量之间的关系可以用来间接探测真实的GC中的BH群体。在这里，我们估计的数量和总质量的BH在50个银河系GC从高级相机的调查GC调查。对于每个GC，Δ是在观察到的主序列群体之间测量的，并被输入到我们的CMC簇目录模型中发现的Δ和BH保留之间的相关性中。我们证明，从我们的模型中测量的Δ的范围与观察到的GC在很大程度上相匹配。我们的研究结果构成了最大的样本GC BH人口已被预测到目前为止，使用自洽和强大的统计方法。我们确定NGC 2808，5927，5986，6101和6205保留特别大的BH种群，每个总BH质量超过103。
Recent numerical simulations of globular clusters (GCs) have shown that stellar-mass black holes (BHs) play a fundamental role in driving cluster evolution and shaping their present-day structure. Rapidly mass-segregating to the center of GCs, BHs act as a dynamical energy source via repeated superelastic scattering, delaying the onset of core collapse and limiting mass segregation for visible stars. While recent discoveries of BH candidates in Galactic and extragalactic GCs have further piqued interest in BH-mediated cluster dynamics, numerical models show that even if significant BH populations remain in today’s GCs, they are not typically in directly detectable configurations. We demonstrated in Weatherford et al. that an anticorrelation between a suitable measure of mass segregation (Δ) in observable stellar populations and the number of retained BHs in GC models can be applied to indirectly probe BH populations in real GCs. Here we estimate the number and total mass of BHs in 50 Milky Way GCs from the Advanced Camera for Surveys GC Survey. For each GC, Δ is measured between observed main-sequence populations and fed into correlations between Δ and BH retention found in our CMC Cluster Catalog’s models. We demonstrate that the range in measured Δ from our models matches that for observed GCs to a remarkable degree. Our results constitute the largest sample of GCs for which BH populations have been predicted to date using a self-consistent and robust statistical approach. We identify NGC 2808, 5927, 5986, 6101, and 6205 to retain especially large BH populations, each with a total BH mass exceeding 103 .