Collaborative Research: The Physics of Accretion Disks

AST-0908336/0908869 Krolik/Hawley基于这样的理解，即吸积的基本机制是由磁旋转不稳定性驱动的磁流体动力学（MHD）湍流引起的角动量输运，因此有可能详细研究黑洞吸积的天体物理性质。 在之前的NSF支持下，该团队开发了一套牛顿和广义相对论MHD数值模拟代码，适用于探索黑洞吸积流及其有时产生的喷流的全局特性。 这个由Krolik博士领导的合作项目现在将扩展以前的工作，以考虑吸积热力学和能量学，大规模磁场的影响，以及吸积流如何在大距离处倾斜于黑洞旋转轴与Lense-Thirring扭矩相互作用。 重点将放在整个创建动力学模拟数据和可观察的properties之间的定量链接。这项工作应该提供真正的指导的争议有多少大规模的磁通量可能会带来深入吸积流。 它还应该揭示如何吸积流强调磁场与内在的大尺度结构可能不同于那些没有。 此外，计算吸积流内的MHD应力对于引力磁力引起的盘弯曲程度的问题是必不可少的，并且应该很快就可以计算出具有足够分辨率的盘结构来解决这个问题。来自特定模型的模拟代码和数据将提供给社区，加强学科的软件基础设施。 该项目将为研究生提供数值模拟技术方面的培训。 将继续根据模拟结果开展成功的公众宣传工作，包括天文馆表演和电视纪录片。

AST-0908336/0908869Krolik/HawleyArmed by an understanding that the fundamental mechanism of accretion is angular momentum transport due to magnetohydrodynamic (MHD) turbulence driven by the magneto-rotational instability, it has become possible to investigate at a detailed level the astrophysical properties of accretion onto black holes. With previous NSF support, this team has developed a suite of Newtonian and general relativistic MHD numerical simulation codes suitable for exploring the global properties of accretion flows onto black holes and the jets they sometimes generate. This collaborative project, led by Dr. Krolik, will now extend prior work to consider accretion thermodynamics and energetics, the impact of large-scale magnetic fields, and how an accretion flow oriented obliquely to the black hole rotation axis at large distances interacts with Lense-Thirring torques. Emphasis will be placed throughout on creating quantitative links between dynamical simulation data and observable properties.This work should provide genuine guidance for the controversy over how much large-scale magnetic flux may be brought deep into the accretion flow. It should also reveal how accretion flows stressed by magnetic fields with intrinsic large-scale structure may differ from those without. In addition, computing MHD stresses within the accretion flow is essential to the question of the extent of disk bending by gravitomagnetic forces, and it should soon be possible to calculate disk structure with sufficient resolution to address this issue.Both simulation codes and data from specific models will be made available to the community, strengthening the software infrastructure of the discipline. The project will provide graduate student training in numerical simulation techniques. Successful public outreach efforts based on simulation results will continue, including planetarium shows and television documentaries.