Quasi-periodic Behavior of Mini-disks in Binary Black Holes Approaching Merger
Quasi-periodic Behavior of Mini-disks in Binary Black Holes Approaching Merger
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DOI：
10.3847/2041-8213/aaa756
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发表时间：
2018-01-20
影响因子：
7.9
通讯作者：
Zilhao, Miguel
中科院分区：
文献类型：
--
作者：
Bowen, Dennis B.;Mewes, Vassilios;Zilhao, Miguel
我们提出了第一个磁流体动力学模拟中，一个相对论性的二元黑洞周围的circumbinary磁盘饲料质量个别吸积盘（“迷你磁盘”）周围的每个黑洞。通过连接环双星盘和迷你盘的吸积流的质量流被准周期性地调制，这是由于流与环双星盘内边缘的非线性密度特征（或称“团块”）的相互作用：供应每个迷你盘的流以0.74倍于双星轨道频率的频率与团块进入相位。由于双星是相对论性的，迷你盘的潮汐截断半径并不比它们最内层的稳定圆轨道大多少;因此，迷你盘的流入时间比传统的估计要短，并且与流调制周期相当。因此，小圆盘总是处于流入不平衡状态，其质量和螺旋密度波结构响应于流的准周期调制。每个小圆盘质量的波动是如此之大，以至于整个小圆盘质量的75%可以包含在一个小圆盘中。这种准周期调制的迷你磁盘结构可能会引入独特的时间依赖性的特点，在二进制的电磁辐射。
We present the first magnetohydrodynamic simulation in which a circumbinary disk around a relativistic binary black hole feeds mass to individual accretion disks ("mini-disks") around each black hole. Mass flow through the accretion streams linking the circumbinary disk to the mini-disks is modulated quasi-periodically by the streams' interaction with a nonlinear m = 1 density feature, or "lump," at the inner edge of the circumbinary disk: the stream supplying each mini-disk comes into phase with the lump at a frequency 0.74 times the binary orbital frequency. Because the binary is relativistic, the tidal truncation radii of the mini-disks are not much larger than their innermost stable circular orbits; consequently, the mini-disks' inflow times are shorter than the conventional estimate and are comparable to the stream modulation period. As a result, the mini-disks are always in inflow disequilibrium, with their masses and spiral density wave structures responding to the stream's quasi-periodic modulation. The fluctuations in each mini-disk's mass are so large that as much as 75% of the total mini-disk mass can be contained within a single mini-disk. Such quasi-periodic modulation of the mini-disk structure may introduce distinctive time-dependent features in the binary's electromagnetic emission.