分层黑洞三体系统中并合时间的精度
The accuracy of merger times in hierarchical black hole triples
- California Institute of Technology（加州理工学院）
- 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总结：
本研究通过对比轨道平均与非轨道平均方程，发现分层三体系统中黑洞双星的并合时间估计在多数情况下保持准确，但极端高偏心率致密双星中差异显著，并强调非轨道平均效应对推断形成通道的重要性。
AI中文摘要：
轨道平均方程被广泛用于模拟致密双星系统的引力波驱动演化。其有效性依赖于辐射反作用时标远长于轨道周期，这一假设对于高偏心率系统可能失效。在本工作中，我们通过比较轨道平均与非轨道平均方案，研究轨道平均对并合时间估计的影响。我们将分析应用于分层三体系统中两类具有天体物理动机的黑洞双星种群，其中von Zeipel-Lidov-Kozai振荡可将内双星偏心率驱动至接近1。我们发现，在广泛的偏心率范围内，即使轨道时标超过辐射反作用时标，由轨道平均方程得到的并合时间估计仍保持显著准确。显著的差异仅出现在最极端且最致密的双星系统中，这些系统同时具有非常高的偏心率和较小的半通径。在该区域，并合时间强烈依赖于初始轨道相位，不同相位给出的预测可相差数个数量级。我们还将结果与专门为分层三体系统开发的轨道平均并合时间方案进行比较，发现在高偏心率区域，该方案与通用的轨道平均及非轨道平均计算结果之间存在显著差异。虽然这些结果证明了轨道平均并合时间估计对大多数系统的稳健性，但它们也强调了当并合时间被用于推断致密双星延迟时间分布和形成通道时，非轨道平均效应可能具有的重要性。
英文摘要：
Orbit-averaged equations are widely used to model the gravitational-wave-driven evolution of compact binaries. Their validity relies on the radiation-reaction timescale being much longer than the orbital period, an assumption that can break down for highly eccentric systems. In this work, we investigate the impact of orbit averaging on merger-time estimates by comparing orbit-averaged and non-orbit-averaged prescriptions. We apply our analysis to two different astrophysically motivated populations of black hole binaries in hierarchical triple systems, where von Zeipel-Lidov-Kozai oscillations can drive the inner binary eccentricities close to unity. We find that merger-time estimates obtained with orbit-averaged equations remain remarkably accurate across a wide range of eccentricities, even when the orbital timescale exceeds the radiation-reaction timescale. Significant discrepancies arise only for the most extreme and compact binaries, simultaneously characterized by very high eccentricities and small semi-latus recta. In this regime, the merger time becomes strongly dependent on the initial orbital phase, with different phases yielding predictions that can differ by several orders of magnitude. We also compare our results with an orbit-averaged merger-time prescription specifically developed for hierarchical triple systems and find substantial differences between this prescription and both the generic orbit-averaged and non-orbit-averaged calculations in the high-eccentricity regime. While these results demonstrate the robustness of orbit-averaged merger-time estimates for most systems, they also highlight the potential importance of non-orbit-averaged effects when merger times are used to infer compact-binary delay-time distributions and formation channels.
