发表机构
Max Planck Institute for Gravitational Physics (Albert Einstein Institute); University of Texas at Austin; Leibniz Universität Hannover; Institute for Advanced Study, Princeton（马克斯·普朗克引力物理研究所（爱因斯坦研究所）; 德克萨斯大学奥斯汀分校; 汉诺威莱布尼茨大学; 普林斯顿高等研究院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出一种从半解析模型直接获取应变概率密度的方法，桥接超大质量双黑洞布居合成与引力波背景观测，并验证了其对NANOGrav数据的复现及对Illustris模拟的映射。
AI 中文摘要
脉冲星计时阵列（PTAs）通过观测引力波背景（GWB）来约束超大质量双黑洞（SMBHBs）的布居性质。不同于其他方法对布居合成库进行插值或仅考虑应变谱的平均值，本文直接从半解析布居模型中捕获其完整的应变概率密度。我们将新方法应用于半解析SMBHB布居模型，独立复现了NANOGrav合作组利用其15年数据对该模型进行的参数估计。我们还展示了GWB中离散SMBHB贡献在多大程度上消除布居参数空间中的简并。最后，以源计数强度作为计算中的中间产物，作为原理验证，我们将PTA观测映射到基于数值流体动力学模拟“Illustris”的星系并合方案的SMBHB模型。我们发现星系并合后千秒差距到亚秒差距尺度SMBHB间距之间的延迟时间τ的影响，对于τ高达8 Gyr，h_c在(1-6)×10^-16范围内，N_c在(0.3-7.1)×10^-3范围内。
英文摘要
Pulsar Timing Arrays (PTAs) constrain population properties of supermassive binary black holes (SMBHBs) through the observation of the gravitational wave background (GWB). Unlike other approaches that interpolate population-synthesis libraries or only consider the mean of the strain spectrum, here we capture its full strain probability density directly from semi-analytic population models. We apply our new method to the semi-analytic SMBHB population model, independently reproducing the parameter estimation for this model performed by the NANOGrav Collaboration with their 15-yr data. We also show the extent to which discrete SMBHB contributions to the GWB resolve degeneracies in the population parameter space. Finally, using the source-count intensity as the intermediate product in our calculation, we map PTA observations, as a proof of principle, to the SMBHB model based on the galaxy merger prescriptions from numerical hydrodynamical simulations "Illustris". We find the effect of delay times $τ$ between kiloparsec and subparsec SMBHB separations following galaxy mergers, finding $h_{\rm c}$ spanning $(1$-$6)\times10^{-16}$ and $N_{\rm c}$ spanning $(0.3$-$7.1)\times10^{-3}$ for $τ$ up to 8 Gyr.
Comments13 pages, 5 figures
