论文标题
AGN磁盘中黑洞二进制的世俗自旋轨道共振
Secular Spin-orbit Resonances of Black Hole Binaries in AGN Disks
论文作者
论文摘要
恒星质量黑洞（SBH）二进制的自旋轨道未对准对合并SBH的形成通道提供了重要的限制。在这里，我们研究了世俗的自旋轨道共振在AGN磁盘中超质量BH（SMBH）周围SBH二元组分进化中的作用。由于磁盘的翘曲/破坏半径内的curl curment Moment介绍了SBH的旋转需求。我们发现，SBH的自旋轨道未对准（倾斜）可以通过SBH二进制轨道轨道淋巴结进动与由大量圆周SBH磁盘驱动的SBH Spin-Preastion之间的自旋轨道共振激发。使用$α$ disk型号，带有Bondi-Hoyle-Lyttleton积聚，通常发生共振的SBH Binaries，其半高轴为$ 1 $ au，并且在$ \ sim 1000 $ au $ 10^7 $ \ msun smbh左右的距离。自旋轨道共振会导致高SBH倾斜，并大量SBH二元自旋旋转未对准。但是，我们注意到，邦迪 - 霍伊尔 - 莱特顿积聚远高于爱丁顿的增生，这通常会导致旋转进液太低而无法触发旋转轨道共振。因此，对于AGN磁盘中的SBH，世俗的自旋轨道共振可能很少。
The spin-orbit misalignment of stellar-mass black hole (sBH) binaries provide important constraints on the formation channels of merging sBHs. Here, we study the role of secular spin-orbit resonance in the evolution of a sBH binary component around a supermassive BH (SMBH) in an AGN disk. We consider the sBH's spin-precession due to the $J_2$ moment introduced by a circum-sBH disk within the warping/breaking radius of the disk. We find that the sBH's spin-orbit misalignment (obliquity) can be excited via spin-orbit resonance between the sBH binary's orbital nodal precession and the sBH spin-precession driven by a massive circum-sBH disk. Using an $α$-disk model with Bondi-Hoyle-Lyttleton accretion, the resonances typically occur for sBH binaries with semi-major axis of $1$AU, and at a distance of $\sim 1000$AU around a $10^7$\msun SMBH. The spin-orbit resonances can lead to high sBH obliquities, and a broad distribution of sBH binary spin-spin misalignments. However, we note that the Bondi-Hoyle-Lyttleton accretion is much higher than that of Eddington accretion, which typically results in spin precession being too low to trigger spin-orbit resonances. Thus, the secular spin-orbit resonances can be quite rare for sBHs in AGN disks.
