An Eccentric Circumbinary Accretion Disk and the Detection of Binary Massive Black Holes
An Eccentric Circumbinary Accretion Disk and the Detection of Binary Massive Black Holes
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DOI：
10.1086/523869
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发表时间：
2006-07
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影响因子：
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通讯作者：
A. MacFadyen;M. Milosavljevic
中科院分区：
文献类型：
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作者：
A. MacFadyen;M. Milosavljevic
我们给出了一种基于网格的二维流体动力学模拟方法，模拟了一个薄的、粘性的、局部等温的旋转圆盘在固定的圆形轨道上绕一个等质量的牛顿二元点质量旋转。研究了多次粘性作用后圆盘的结构。二元体在粘性松弛盘上保持中心孔，其半径大约等于二元体半长轴的两倍。孔内的盘表面密度相对于盘体积中的密度减少了数量级。圆盘的内部截断类似于原行星圆盘上空隙的清除。最初的圆盘变成椭圆形，然后变成偏心的。圆盘中的扰动包含一个静止在双星静止的旋转框架中的分量；该分量是双臂螺旋密度波。我们测量了盘中二元扭矩的分布，发现在中心低密度孔内施加的正扭矩最大。我们将圆盘外力的线性理论联系起来，发现3：2(m=2)的力矩密度分布与中心孔内的力矩密度分布是一致的。我们还测量了气体在空穴中吸积的速率与时间的关系，发现了准周期结构。我们讨论了包含一个双质量黑洞的活动星系核的可变性和探测的含义。
We present a two-dimensional grid-based hydrodynamic simulation of a thin, viscous, locally isothermal corotating disk orbiting an equal-mass Newtonian binary point mass on a fixed circular orbit. We study the structure of the disk after multiple viscous times. The binary maintains a central hole in the viscously relaxed disk with radius equal to about twice the binary semimajor axis. Disk surface density within the hole is reduced by orders of magnitude relative to the density in the disk bulk. The inner truncation of the disk resembles the clearing of a gap in a protoplanetary disk. An initially circular disk becomes elliptical and then eccentric. Disturbances in the disk contain a component that is stationary in the rotating frame in which the binary is at rest; this component is a two-armed spiral density wave. We measure the distribution of the binary torque in the disk and find that the strongest positive torque is exerted inside the central low-density hole. We make connection with the linear theory of disk forcing at outer Lindblad resonances (OLRs) and find that the measured torque density distribution is consistent with forcing at the 3:2 (m = 2) OLR, well within the central hole. We also measure the time dependence of the rate at which gas accretes across the hole and find quasi-periodic structure. We discuss implications for variability and detection of active galactic nuclei containing a binary massive black hole.