Monte Carlo Population Synthesis on Massive Star Binaries: Astrophysical Implications for Gravitational-wave Sources
Monte Carlo Population Synthesis on Massive Star Binaries: Astrophysical Implications for Gravitational-wave Sources
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DOI：
10.3847/1538-4357/aae378
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发表时间：
2017-10
期刊：
影响因子：
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通讯作者：
I. Ablimit;K. Maeda
中科院分区：
文献类型：
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作者：
I. Ablimit;K. Maeda
在双致密恒星双星(DCB；黑洞-黑洞(BH-BH)，BH-中子星(BH-NS)，NS-NS系统)的标准形成情景中，有一些重要但尚未解决的过程，如质量传递和公共包络(CE)相。我们用双粒子数合成方法分析了不同的假设对大质量恒星双星演化的关键物理过程和双星初始条件的影响，包括对CE相中质量传递(QCR)和结合能参数(λ)提出的公式的综述。我们发现QCR明显影响NS-NS系统的性质，而λ对BH-BH系统的质量分布有影响。高效的CE喷射提高了DCB的合并率，在我们的处方中，这与结合能参数有关，包括所有可能的预算到能量含量。认为GW150914和GW151226的性能差异可能反映了不同的金属丰度。我们用我们的BPS计算再现了它们的性质，发现在低金属丰度下BH-BH体系的性质对λ很敏感；有效的Ce抛射导致了一次和二次BHS的顶重质量分布，这有利于解释GW150914的性质。有效的CE抛射还导致了BH-BH和NS-NS合并率的提高，达到了与GW170817等探测到的引力波源的观测约束相一致的水平。
There are important but unresolved processes in the standard formation scenarios of double compact star binaries (DCBs; black hole–black hole (BH–BH), BH–neutron star (BH–NS), NS–NS systems), such as mass transfer and the common envelope (CE) phase. We analyze the effects of different assumptions on key physical processes and binary initial conditions on massive star binary evolution with binary population synthesis (BPS), including a survey of proposed prescriptions for the mass transfer (qcr) and the binding energy parameter (λ) in the CE phase. We find that qcr clearly affects the properties of NS–NS systems while λ has an influence on the mass distributions of BH–BH systems. The merger rates of DCBs are increased by efficient CE ejection, which in our prescription is related to the binding energy parameter, including all the possible budgets to the energy content. It has been suggested that the difference in the properties of GW150914 and GW151226 may reflect different metallicity. We reproduce their properties with our BPS calculations and find that the property of BH–BH systems at low metallicity is sensitive to λ; the efficient CE ejection leads to a top-heavy mass distribution both for the primary and secondary BHs, which is favored to explain the nature of GW150914. The efficient CE ejection also leads to enhancement of both the BH–BH and NS–NS merger rates to the level consistent with the observational constraints from the detected gravitational-wave sources, including GW170817.