Beyond Shakura-Sunyaev: First-Principles Physics of Accretion Disks in Active Galactic Nuclei

超越 Shakura-Sunyaev：活动星系核中吸积盘的第一原理物理学

• 批准号: 0307657
• 负责人: Omer Blaes
• 金额: --
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0307657&HistoricalAwards=false
• 关键词: Beyond; Shakura; Sunyaev; First; Principles

AST-0307657BlaesThe mechanism responsible for the prodigious power output of quasars and active galactic nuclei is almost certainly the accretion of plasma onto super-massive black holes, probably in the form of a rotationally supported accretion disk. The standard model of accretion disks has been based on an ad hoc phenomenological prescription for turbulent angular momentum transport and energy dissipation, introduced by Shakura & Sunyaev some thirty years ago.The current research will create local, radiation-magnetohydrodynamical simulations of this accretion flow, for the first time with no ad-hoc assumptions, which should finally lift the long-standing uncertainties in the standard model. The power and sophistication of modern numerical techniques will be used to determine whether there is an achievable thermally stable equilibrium state, how much turbulent stress is present in radiation-pressure-dominated flows, the average vertical distribution in the flow, and the rates of heat and energy transport. The work will also consider compressibility, density inhomogeneities, and the nonlinear development of photon-bubble and magnetoacoustic-wave instabilities.Snapshots of the turbulent state at different locations in the flow will be made available for scientists everywhere, to add other physics or consider additional effects. Some tests will be possible for the first time because the models will be based on physics and not phenomenological prescriptions. Graduate and undergraduate students will be involved in the research. Animations of the simulation results will be effective as part of the investigators' public talks about the interesting complexity of black hole astrophysics, which continues to fascinate.

AST-0307657Blaes 类星体和活动星系核产生巨大功率输出的机制几乎可以肯定是等离子体在超大质量黑洞上的吸积，可能以旋转支撑的吸积盘的形式存在。 吸积盘的标准模型基于 Shakura 和 Sunyaev 大约三十年前提出的湍流角动量传输和能量耗散的特殊现象学规定。当前的研究将为这种吸积流创建局部辐射磁流体动力学模拟，第一次没有临时假设，这最终应该消除标准模型中长期存在的不确定性。 现代数值技术的力量和复杂性将用于确定是否存在可实现的热稳定平衡状态、辐射压力主导的流动中存在多少湍流应力、流动中的平均垂直分布以及热速率和能源运输。 这项工作还将考虑可压缩性、密度不均匀性以及光子泡和磁声波不稳定性的非线性发展。流动中不同位置的湍流状态快照将为世界各地的科学家提供，以添加其他物理现象或考虑其他物理现象影响。 一些测试将首次成为可能，因为这些模型将基于物理学而不是现象学规定。 研究生和本科生将参与这项研究。 模拟结果的动画将作为研究人员公开谈论黑洞天体物理学有趣的复杂性的一部分，这一点仍然令人着迷。