论文标题
嵌入在AGN磁盘中的恒星质量黑洞的自旋进化：轨道偏心率会产生逆行折叠式流动
Spin Evolution of Stellar-mass Black Holes Embedded in AGN disks: Orbital Eccentricity Produces Retrograde Circumstellar Flows
论文作者
论文摘要
嵌入AGN积聚磁盘中的恒星质量黑洞（SBHS）的自旋进化是与通过AGN通道从二元黑洞（BBH）合并事件中产生引力波的重要过程。由于嵌入的SBHS被周围的磁盘（CSD）包围，因此CSD气流的旋转决定了其积聚的角动量的方向。 In this Letter, we use global 2D hydrodynamic simulations to show that while a disk-embedded sBH on a circular orbit transforms the initial retrograde Keplerian shear of the background accretion disk into a prograde CSD flow, as in the classical picture of companion-disk interaction theory, moderate orbital eccentricity could disrupt the steady-state tidal perturbation and preserve a retrograde CSD flow around the SBH。这种CSD方向的转换发生在过渡偏心率上，该转换与局部音速几乎成正比。 CSD流中的分叉及其SBHS的旋转方向导致形成几乎抗对约的SBHS的人群，并应将其纳入未来的SBH和BBH演变的人群模型中。
Spin evolution of stellar-mass Black Holes (sBHs) embedded in AGN accretion disks is an important process relevant to production of gravitaional waves from binary Black Hole (BBH) merger events through the AGN channel. Since embedded sBHs are surrounded by circum-stellar disks (CSDs), the rotation of CSD gas flows determine the direction of the angular momentum it accretes. In this Letter, we use global 2D hydrodynamic simulations to show that while a disk-embedded sBH on a circular orbit transforms the initial retrograde Keplerian shear of the background accretion disk into a prograde CSD flow, as in the classical picture of companion-disk interaction theory, moderate orbital eccentricity could disrupt the steady-state tidal perturbation and preserve a retrograde CSD flow around the sBH. This switch of CSD orientation occurs at a transition eccentricity that scales nearly proportional with local sound speed. This bifurcation in the CSD flow and thereafter spin-up direction of SBHs leads to formation of a population of nearly anti-aligned sBHs and should be incorporated in future population models of sBH and BBH evolutions.
