Monte Carlo simulations of the evolution of galactic nuclei containing massive, central black holes
Monte Carlo simulations of the evolution of galactic nuclei containing massive, central black holes
复制标题
包含大质量中心黑洞的星系核演化的蒙特卡罗模拟
DOI：
10.1086/160980
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
S. Shapiro
中科院分区：
文献类型：
--
作者：
M. Duncan;S. Shapiro
本文修改了一个以前用于研究球状星团动力学演化的Monte Carlo方案，使之能模拟含有大质量中心黑洞的致密星系核的演化。黑洞被假设为吸积恒星的碎片，这些碎片要么被黑洞潮汐破坏，要么在与其他恒星的直接物理碰撞中被摧毁。蒙特卡罗的结果证实了早期的估计，在球形集群的最大可达到的潮汐中断率大致是由中央两体弛豫时间除以核心的质量。假设约10%的吸积质量转化为辐射，由此产生的光度是典型的塞弗特核，但低于类星体的光度福尔斯，除了在系统中的物理碰撞是一个更重要的燃料源比潮汐中断。发现最大物理碰撞率大致为核心质量除以中心碰撞时间尺度，因此碰撞可以提供足够的燃料来产生类星体亮度。最亮的阶段持续大约一个碰撞时间，之后的光度标度为t/sup-1/。三轴偏离球度约5%的核心（如果它们存在）也可以提高潮汐破坏率类星体的水平。所有主要的蒙特卡罗结果，包括更多»后期行为，都可以用简单的解析标度律来解释。由于束缚恒星的潮汐破坏系统的加热被发现在很大程度上被由于未束缚恒星的破坏而产生的冷却效应所抵消，因此用于黑洞球状星团演化的同调模型不适用于这些模拟。我们的模拟类星体的星等和红移的影响进行了简要的考虑。«少
A Monte Carlo scheme previously used to study the dynamical evolution of globular clusters is modified to simulate the evolution of dense galactic nuclei containing massive central black holes. The black hole is assumed to accrete the debris from stars which are either tidally disrupted by the hole or destroyed in direct physical collisions with other stars. The Monte Carlo results confirm earlier estimates that the maximum attainable tidal disruption rate in spherical clusters is roughly the mass of the core divided by the central two-body relaxation time. Assuming approx.10% conversion of accreted mass into radiation, the resulting luminosity is typical Seyfert nuclei but falls below quasar luminosities, except in systems in which physical collisions are a more important fuel source than tidal disruption. Maximum physical collision rates are found to be roughly the mass of the core divided by the central collision time scale, so collisions can provide sufficient fuel to produce quasar luminosities. The brightest phase lasts about one collision time, after which the luminosity scales as t/sup -1/. Triaxial deviations from sphericity of approx.5% in the core (if they exist) can also boost tidal disruption rates to quasar levels. All of the major Monte Carlo results, includingmore » late-time behavior, are explained by simple analytic scaling laws. The heating of the system due to tidal disruption of bound stars is found to be largely canceled by cooling effects due to the disruption of unbound stars, so that the homological models used for the evolution of globular clusters with black holes do not apply to these simulations. The implications of our simulations for quasar magnitudes and redshifts are briefly considered.« less