A new Monte Carlo code for star cluster simulations - I. Relaxation
A new Monte Carlo code for star cluster simulations - I. Relaxation
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用于星团模拟的新蒙特卡罗代码 - I. 松弛
DOI：
10.1051/0004-6361:20010706
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发表时间：
2001
影响因子：
6.5
通讯作者：
Bern University
中科院分区：
文献类型：
--
作者：
M. Freitag;Willy Benz Geneva Observatory;Bern University
我们已经开发了一个新的模拟代码，旨在研究围绕着一个大质量黑洞的银河系中心星星集群的恒星动力学。为了包括所有相关的物理成分（2体松弛，恒星质谱，碰撞，潮汐破坏，......），我们选择恢复由H埃农在70年代开创的数值方案（H埃农1971 b，a; H埃农1973.它基本上是福克-普朗克方程的蒙特卡罗解。它可以科普任何恒星的质量谱或速度分布。作为一种基于粒子的方法，它还允许人们以非常现实的方式考虑恒星碰撞。本文介绍了我们的程序的基本版本，它处理了没有中心BH的星团的弛豫驱动演化。文中给出了该规范的技术说明以及试验计算结果。由于使用的二叉树存储潜在的和排名的信息和可变的时间步长，集群模型与多达2 - 10 - 6粒子可以模拟在一个标准的个人计算机和CPU时间所需的尺度为Np ln（NP）与粒子数NP。此外，模拟恒星的数量不需要等于Np，而是可以任意大。一个配套文件将处理进一步的物理元素，主要是有关星系核。
We have developed a new simulation code aimed at studying the stellar dynamics of a galactic central star cluster surrounding a massive black hole. In order to include all the relevant physical ingredients (2-body relaxation, stellar mass spectrum, collisions, tidal disruption, ...) , we chose to revive an umerical scheme pioneered by H enon in the 70's (H enon 1971b,a; H enon 1973. It is basically a Monte Carlo resolution of the Fokker-Planck equation. It can cope with any stellar mass spectrum or velocity distribution. Being a particle-based method, it also allows one to take stellar collisions into account in a very realistic way. This rst paper covers the basic version of our code which treats the relaxation-driven evolution of a stellar cluster without a central BH. A technical description of the code is presented, as well as the results of test computations. Thanks to the use of a binary tree to store potential and rank information and of variable time steps, cluster models with up to 2 10 6 particles can be simulated on a standard personal computer and the CPU time required scales as Np ln(Np) with the particle number Np. Furthermore, the number of simulated stars needs not be equal to Np but can be arbitrarily larger. A companion paper will treat further physical elements, mostly relevant to galactic nuclei.