EXCITATION OF TRAPPED WAVES IN SIMULATIONS OF TILTED BLACK HOLE ACCRETION DISKS WITH MAGNETOROTATIONAL TURBULENCE
EXCITATION OF TRAPPED WAVES IN SIMULATIONS OF TILTED BLACK HOLE ACCRETION DISKS WITH MAGNETOROTATIONAL TURBULENCE
复制标题
磁旋转湍流倾斜黑洞吸积盘模拟中俘获波的激发
DOI：
10.1088/0004-637x/706/1/705
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Barbara T. Ferreira
中科院分区：
文献类型：
--
作者：
K. B. Henisey;O. Blaes;P. C. Fragile;Barbara T. Ferreira
我们分析了无量纲自旋参数 a/M = 0.9 的黑洞吸积流的一般相对论、磁流体动力学模拟中流体变量的时间依赖性。我们考虑吸积材料的角动量与黑洞自旋轴对齐（倾斜流）和错位 15°（倾斜流）的两种情况。与倾斜模拟相比，倾斜模拟表现出明显过量的惯性变化，即低于局部径向周转频率的频率变化。我们通过关注在三个分析流体变量中的每一个中发现的 118(M/10 M☉)−1 Hz 的径向扩展频带来进一步研究这种类惯性功率的径向结构。该频率下的三维密度结构表明，功率是一种复合振荡，其主要成分是与背景流共转的过密团块、低阶惯性波和低阶惯性声波。我们的结果初步证实了早期的建议，即盘倾斜可能是惯性波的重要激发机制。
We analyze the time dependence of fluid variables in general relativistic, magnetohydrodynamic simulations of accretion flows onto a black hole with dimensionless spin parameter a/M = 0.9. We consider both the cases where the angular momentum of the accretion material is aligned with the black hole spin axis (an untilted flow) and where it is misaligned by 15° (a tilted flow). In comparison to the untilted simulation, the tilted simulation exhibits a clear excess of inertial variability, that is, variability at frequencies below the local radial epicyclic frequency. We further study the radial structure of this inertial-like power by focusing on a radially extended band at 118(M/10 M☉)−1 Hz found in each of the three analyzed fluid variables. The three-dimensional density structure at this frequency suggests that the power is a composite oscillation whose dominant components are an over dense clump corotating with the background flow, a low-order inertial wave, and a low-order inertial-acoustic wave. Our results provide preliminary confirmation of earlier suggestions that disk tilt can be an important excitation mechanism for inertial waves.