核星团中的共振动力学摩擦：中等质量黑洞与星盘的快速对准
Resonant Dynamical Friction in Nuclear Star Clusters: Rapid Alignment of an Intermediate-mass Black Hole with a Stellar Disk
摘要：
我们研究了一个中等质量黑洞（IMBH）的动力学演化在一个核星团托管一个超大质量黑洞（SMBH）和一个球形和扁平盘状分布的恒星质量的对象。我们使用直接N体（phiGPU）和轨道平均（N环）数值积分模拟恒星和IMBH的轨道演化。我们发现，如果IMBH的轨道与恒星盘的初始倾角小于90度，则它们的轨道逐渐与恒星盘对齐。如果大于90度，即反向旋转，则IMBH不对齐。最初，轨道重定向的速率随着IMBH的质量与SMBH质量的比率线性增加，并且比普通的（即rasekhar）动力学摩擦快几个数量级，特别是对于高SMBH质量。IMBH和恒星的半长轴近似守恒。这表明，这种排列主要是由恒星的轨道平均引力矩驱动的，这一过程可以称为共振动力学摩擦。恒星盘被IMBH扭曲，并最终增加其厚度。这一过程可能为IMBH候选者在银河系中心的生存能力提供了一个测试。共振动力学摩擦并不局限于IMBH;任何比盘粒子质量大得多的物体最终都可能与盘对齐。这可能对致密恒星系统中黑洞盘的形成和演化以及LIGO、VIRGO、KAGRA和LISA的引力波源种群有影响。
英文摘要：
We investigate the dynamical evolution of an intermediate-mass black hole (IMBH) in a nuclear star cluster hosting a supermassive black hole (SMBH) and both a spherical and a flattened disk-like distribution of stellar-mass objects. We use a direct N-body (phiGPU) and an orbit-averaged (N-ring) numerical integrator to simulate the orbital evolution of stars and the IMBH. We find that the IMBH's orbit gradually aligns with the stellar disk if their mutual initial inclination is less than 90 degree. If it is larger than 90 degree, i.e. counterrotating, the IMBH does not align. Initially, the rate of orbital reorientation increases linearly with the ratio of the mass of the IMBH over the SMBH mass and it is orders of magnitude faster than ordinary (i.e. Chandrasekhar) dynamical friction, particularly for high SMBH masses. The semimajor axes of the IMBH and the stars are approximately conserved. This suggests that the alignment is predominantly driven by orbit-averaged gravitational torques of the stars, a process which may be called resonant dynamical friction. The stellar disk is warped by the IMBH, and ultimately increases its thickness. This process may offer a test for the viability of IMBH candidates in the Galactic Center. Resonant dynamical friction is not limited to IMBHs; any object much more massive than disk particles may ultimately align with the disk. This may have implications for the formation and evolution of black hole disks in dense stellar systems and gravitational wave source populations for LIGO, VIRGO, KAGRA, and LISA.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
