On the Rate of Neutron Star Binary Mergers from Globular Clusters
On the Rate of Neutron Star Binary Mergers from Globular Clusters
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DOI：
10.3847/2041-8213/ab5dc5
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发表时间：
2019-10
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影响因子：
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通讯作者：
Claire S. Ye;W. Fong;K. Kremer;C. Rodriguez;S. Chatterjee;G. Fragione;F. Rasio
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文献类型：
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作者：
Claire S. Ye;W. Fong;K. Kremer;C. Rodriguez;S. Chatterjee;G. Fragione;F. Rasio
首次探测到中子星-中子星合并（GW170817）的引力波，以及越来越多的短伽马射线暴观测，极大地推动了对中子星-中子星（NS-NS）和中子星-黑洞（NS-BH）双星起源的研究。我们利用CMC的星团目录模拟了球状星团（GC）中NS-NS和NS-BH双星的合并率。我们使用了大量的模型样本，这些模型具有一系列初始恒星数量、金属丰度、维里半径和星系中心距离，代表了当今银河系的GCs，以量化启发时间和体积合并率作为红移的函数，无论是在星团内部还是从星团中喷出。我们发现，在大多数GCs的整个生命周期中，恒星黑洞主导了星团核心，并阻止了NSs的质量分离，从而降低了NSs的动态相互作用速率，因此最多只能产生少量的NS双星合并。我们估计NS-NS和NS-BH双星在本地宇宙中的合并速率为~ 0.02 Gpc−3 yr−1，或者两个种群的合并速率为~ 0.04 Gpc−3 yr−1。这些速率比激光干涉仪引力波天文台/处女座目前的经验合并速率低5个数量级。我们得出的结论是，GCs中的动态相互作用对提高NS-NS和NS-BH合并率没有显著作用。
The first detection of gravitational waves from a neutron star–neutron star (NS–NS) merger, GW170817, and the increasing number of observations of short gamma-ray bursts have greatly motivated studies of the origins of NS–NS and neutron star–black hole (NS–BH) binaries. We calculate the merger rates of NS–NS and NS–BH binaries from globular clusters (GCs) using realistic GC simulations with the CMC Cluster Catalog. We use a large sample of models with a range of initial numbers of stars, metallicities, virial radii, and galactocentric distances, representative of the present-day Milky Way GCs, to quantify the inspiral times and volumetric merger rates as a function of redshift, both inside and ejected from clusters. We find that over the complete lifetime of most GCs, stellar BHs dominate the cluster cores and prevent the mass segregation of NSs, thereby reducing the dynamical interaction rates of NSs so that at most a few NS binary mergers are ever produced. We estimate the merger rate in the local universe to be ∼0.02 Gpc−3 yr−1 for both NS–NS and NS–BH binaries, or a total of ∼0.04 Gpc−3 yr−1 for both populations. These rates are about 5 orders of magnitude below the current empirical merger rate from the Laser Interferometer Gravitational-Wave Observatory/Virgo. We conclude that dynamical interactions in GCs do not play a significant role in enhancing the NS–NS and NS–BH merger rates.