论文标题
AGN磁盘中黑孔二元形成的流体动力学模拟
Hydrodynamical Simulations of Black-Hole Binary Formation in AGN Disks
论文作者
论文摘要
我们研究了使用一系列全局2D流体动力学模拟嵌入AGN磁盘中的两个单个黑洞（BHS）之间的紧密相遇。我们发现，当磁盘密度足够高时，可以通过其围绕单个磁盘的碰撞来形成结合的BH二进制文件。我们的分析表明，在BH对经过其相对轨迹的折缘人之后，气体后阻力可能会减慢BHS的速度，可能迫使两个BHS保持紧密结合。由近距离遭遇形成的二进制可以具有紧凑的半高轴，较大的偏心率和逆行轨道角动量。我们提供了一个拟合公式，可以准确预测近距离遭遇是否可以根据气体质量和相遇的传入能量形成二进制。该拟合公式可以在研究AGN磁盘中BHS动态演变的其他长期模拟中很容易实现。
We study the close encounters between two single black holes (BHs) embedded in an AGN disk using a series of global 2D hydrodynamics simulations. We find that when the disk density is sufficiently high, bound BH binaries can be formed by the collision of their circum-single disks. Our analysis demonstrates that, after a BH pair passes the pericenter of their relative trajectory, a gas post-collision drag may slow down the BHs, possibly forcing the two BHs to stay tightly bound. A binary formed by a close encounter can have a compact semi-major axis, large eccentricity, and retrograde orbital angular momentum. We provide a fitting formula that can accurately predict whether a close encounter can form a binary based on the gas mass and the incoming energy of the encounter. This fitting formula can be easily implemented in other long-term simulations that study the dynamical evolution of BHs in AGN disks.
