Dynamical Studies of the Galactic Center

梅里特博士和他的合作者将使用专用硬件GRAPE，用大约100万个粒子进行直接的n体模拟，研究恒星的运动，以及银河系中心黑洞（质量是太阳的几百万倍）周围尖端处质量较小的黑洞的运动。这将是第一组可以用单个粒子代表银河系中心附近每颗恒星的模拟。模拟将使用一种新的正则化方案来跟踪彼此接近或接近黑洞的恒星；这适用于处理接近的粒子之间的极端质量比，并包括一些相对论效应。该代码将用于研究一个质量约为太阳1万倍的中等质量黑洞如何影响核恒星的轨道，以及中心超大质量黑洞在向内旋转时的形成过程。这些模拟将被用来测试观测到的恒星盘在小于1秒差距尺度上的起源和动态演化模型。最后，研究小组将模拟中心黑洞附近恒星轨道的弛缓，这控制着恒星被推入黑洞吞噬的轨道的速度。这项工作将与欧洲和以色列的国际合作者以及罗切斯特理工学院（RIT）的同事和学生一起进行。由计算机科学和其他学科的本科生和硕士生组成的“GRAPE小组”将致力于可视化软件的开发。Merritt博士还将与RIT校园内的国家聋人技术研究所合作，吸引聋人学生加入GRAPE小组。

Dr. Merritt and his collaborators will use the special-purpose hardware GRAPE to run direct N-body simulations with roughly a million particles, to study the motion of stars and of less massive black holes in a cusp around the Milky Way's central black hole, a few million times as massive as the Sun. This will be the first set of simulations that can represent each star near the Galactic center by a single particle. The simulations will use a new regularization scheme to follow stars that make close approaches to each other or to the black hole; this is adapted to handle extreme mass ratios between the approaching particles, and includes some relativistic effects. The code will be used to investigate how an intermediate-mass black hole of about 10,000 times the Sun's mass would affect the orbits of nuclear stars, and the build-up of the central supermassive black hole, as it spiraled inwards. The simulations will be used to test models for the origin and dynamical evolution of the observed stellar disks on scales below a parsec. Finally, the team will model relaxation of the stellar orbits in the vicinity of the central black hole, which controls how fast stars are nudged onto orbits from which the black hole will swallow them. The work will be carried out with international collaborators in Europe and Israel, as well as colleagues and students at the Rochester Institute of Technology (RIT). The 'GRAPE group' of undergraduates and master's students from computer science and other disciplines will work on the visualization software. Dr Merritt will also work with the National Technical Institute for the Deaf on the RIT campus to attract deaf students into the GRAPE group.