发表机构
Niels Bohr International Academy, Niels Bohr Institute（尼尔斯·玻尔国际学院，尼尔斯·玻尔研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过AGNBI三维混合N体模拟，发现黑洞在活动星系核盘中形成双星并产生“散射带”，偏心率抑制并合率，估算引力波并合率为2-12 Gpc⁻³yr⁻¹。
AI 中文摘要
活动星系核（AGN）是观测到的引力波并合的一个有前景的起源。当前的族群合成模型仅限于一维N体或蒙特卡洛方法，这些方法依赖于统计手段来解析动力学散射。我们利用正在开发的新代码AGNBI，对围绕活动星系核的黑洞（BH）族群进行了三维混合N体模拟，其中对单体和双体天体的近距离相互作用进行了直接模拟。我们的结果表明，双星形成发生在整个活动星系核盘中，尤其是在迁移时间较长的区域。虽然黑洞在迁移陷阱中高效迁移并配对，但它们经常因双星-单星和双星-双星相互作用导致的电离或交换而被打散。在考虑双星-单星和双星-双星相互作用时，我们报告了围绕陷阱半径的形成和并合的径向分布变宽，我们将其描述为“散射带”。我们评估了预先存在的黑洞族群的影响。当我们在黑洞族群中模拟非零偏心率分布时，与无偏心率族群相比，双星形成和并合被抑制了一个数量级，因为更少的黑洞嵌入到活动星系核盘中。我们报告了近似并合率$\mathcal{R}_\mathrm{GW}\approx2\text{--}12\\,\mathrm{Gpc}^{-3}\\,\mathrm{yr}^{-1}$，通过层级并合产生的最大黑洞质量为$10^2\text{--}10^3\\,M_\odot$，其中较低的初始速度弥散产生更大的黑洞。质量和质量比分布相对平坦，表明活动星系核可能更与高质量或不等质量引力波源相关。
英文摘要
Active galactic nuclei (AGN) are a promising origin for observed gravitational wave mergers. Current population synthesis models are limited to 1D N-body or Monte Carlo methods which rely on statistical approaches to resolving dynamical scatterings. We present three-dimensional hybrid $N$-body simulations of a population of black holes (BHs) surrounding an AGN using a new code in development, AGNBI, where close interactions are directly simulated for both single and binary objects. Our results show binary formations occur throughout the AGN disk, particularly where the migration time is long. While BHs efficiently migrate and pair up in migration traps, they are frequently disrupted by ionisation or exchanges from binary-single and binary-binary interactions. We report a broadened radial distribution of formations and mergers about the trap radius when accounting for binary-single and binary-binary interactions, which we describe as a "scattering belt''. We assess the influence of the pre-existing BH population. When we model a non-zero eccentricity distribution in the BH population, the binary formations and mergers are suppressed by an order of magnitude compared to a non-eccentric population as fewer BHs embed in the AGN disk. We report an approximate merger rate of $\mathcal{R}_\mathrm{GW}\approx2\text{--}12\,\mathrm{Gpc}^{-3}\,\mathrm{yr}^{-1}$ with maximum BH masses of $10^2\text{--}10^3\,M_\odot$ through hierarchical mergers, where lower initial velocity dispersions produce larger BHs. The mass and mass ratio distributions are comparatively flat, suggesting AGN may be more relevant for high-mass or unequal-mass gravitational wave sources.
Comments11 pages, 4 figures
