发表机构
Perimeter Institute for Theoretical Physics; Department of Astronomy and Astrophysics, University of California, Santa Cruz; School of Natural Sciences, Institute for Advanced Study; Department of Astrophysical Sciences, Princeton University（Perimeter理论物理研究所; 加州大学圣克鲁兹分校天体物理学与天文学系; 高等研究院自然科学院; 普林斯顿大学天体物理科学系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过三维流体动力学模拟证明，活动星系核盘中的恒星可捕获经过的黑洞，在内部形成并合时间短的黑洞双星，为引力波事件提供可行来源。
AI 中文摘要
嵌入活动星系核（AGN）盘中的恒星可以增长到数百个太阳质量，而同样的盘预计会容纳一群恒星质量黑洞。因此，一颗恒星可能捕获经过的黑洞，将其内部转变为形成致密黑洞双星系统的潜在工厂，并最终成为我们探测器所观测到的引力波事件的来源。我们通过黑洞-恒星遭遇的三维流体动力学模拟来检验这一通道的可行性。作为原理验证，我们采用恒星与黑洞的质量比为34:1，发现捕获不会破坏恒星的结构：它使恒星加热10%-30%，且恒星在整个过程中仅损失不超过约1%的质量。被捕获的黑洞因动力学摩擦而迅速失去其轨道角动量，在恒星动力学时间（不超过约10^4秒）内沉降至恒星中心。如果恒星中心已存在一个黑洞，则两者形成一个束缚双星，其引力波并合时间低于10^4年。根据遭遇的几何结构和速度，所得轨道可能接近圆形或保留显著的偏心率。我们的计算证实，AGN盘中的黑洞-恒星遭遇确实是组装恒星质量黑洞双星并为引力波探测器提供源的可行通道。
英文摘要
Stars embedded in the disks of active galactic nuclei (AGN) can grow to hundreds of solar masses, and the same disks are expected to host a population of stellar-mass black holes. A star may therefore capture passing black holes, turning its interior into a potential factory for forming compact binary black hole systems and, ultimately, for the gravitational-wave events seen by our detectors. We test how readily this channel operates using three-dimensional hydrodynamic simulations of black hole--star encounters. As a proof of principle, we adopt a star-to-black-hole mass ratio of $34\!:\!1$, and find that the capture does not disrupt the structure of the star: it heats the star by $10$--$30\%$, and the star loses only $\lesssim1\%$ of its mass throughout. The captured black hole loses its orbital angular momentum rapidly to dynamical friction, sinking to the stellar center within a stellar dynamical time $\lesssim10^{4}\,$s. If the star already harbors a black hole at its center, the two form a bound binary whose gravitational-wave coalescence time falls below $10^{4}\,$yr. Depending on the geometry and speed of the encounter, the resulting orbit may be nearly circular or retain substantial eccentricity. Our calculations confirm that black hole--star encounters in AGN disks are indeed a viable channel for assembling stellar-mass black hole binaries and supplying sources for gravitational-wave detectors.
