Three Dimensional Radiation GRMHD Simulations of Accretion Flows Around Black Holes

在宇宙中观测到的一些最明亮的物体与接近或高于爱丁顿质量吸积率的黑洞有关。计算机模拟极大地促进了我们对这种吸积的理解，广义相对论（GR）磁流体力学（MHD）代码已经被开发和广泛应用。然而，大多数方法不包括辐射，而少数方法只能处理有限的光学深度。该项目将开发一个可以处理所有光学深度的GR辐射MHD （GRRMHD）代码，并使用它来研究与发光吸积盘相关的一系列问题。该研究小组已经为GR流体动力学开发了一个辐射模块，他们将把它添加到现有的GRMHD代码中。在代码开发过程中，该团队将使用他们已有的方法研究具有辐射和粘度的流体动力圆盘。一旦这项新技术准备就绪，它将被用于辐射磁化磁盘的工作，重点是薄的和厚的辐射主导磁盘的结构，这些磁盘中的不稳定性的作用，以及由辐射加速产生的风和喷流。该团队拥有一些用于代码测试和要求较低的计算的内部计算机能力，但生产运行将使用NSF的XSEDE超级计算机资源。这项研究将提高我们对这些高亮度吸积流的理解，尽管这项工作非常技术性，但它所代表的重大进步应该会引起公众的兴趣。该结果将有助于解释多年来收集的观测数据，并将对星系形成和演化研究中类星体模式反馈的建模非常有价值。首席研究员在指导年轻科学家，特别是女性科学家方面有着良好的记录，并将积极寻求机会让更多的年轻科学家参与这项研究。

Some of the most luminous objects observed in the universe are associated with black holes accreting near or above the Eddington mass accretion rate. Computer simulations have contributed greatly to our understanding of this accretion, and general relativistic (GR) magneto-hydrodynamic (MHD) codes have been developed and applied widely. However, most methods do not include radiation, and the few that do can handle only limited regimes of optical depth. This project will develop a GR radiation MHD (GRRMHD) code that can handle all optical depths, and use it to study a suite of problems related to luminous accretion disks. The research group already has a radiation module developed for GR hydrodynamics, which they will add into their existing GRMHD code. While that code development is underway, the team will study hydrodynamic disks with radiation and viscosity using their pre-existing methods. Once the new technique is ready, it will be used for work on radiative magnetized disks, focusing on the structure of thin and thick radiation-dominated disks, the role of instabilities in these disks, and the generation of winds and jets by radiative acceleration. The team has some in-house computer capacity for code testing and less demanding computations, but production runs will use NSF's XSEDE supercomputer resources.This study will improve our understanding of these high-luminosity accretion flows, and even though the work is very technical, the major advances it represents should spark public interest. The results will help to interpret the observational data that has been collected over the years, and will be very valuable for modeling quasar mode feedback in studies of galaxy formation and evolution. The principal researcher has a strong track record in mentoring young scientists, especially women, and will actively seek opportunities to involve more of them in this research.