Evolution of Star Clusters near the Galactic Center: Fully Self-Consistent N-Body Simulations
Evolution of Star Clusters near the Galactic Center: Fully Self-Consistent N-Body Simulations
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DOI：
10.1086/591483
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发表时间：
2007-08
期刊：
影响因子：
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通讯作者：
M. Fujii;M. Iwasawa;Y. Funato;J. Makino
中科院分区：
文献类型：
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作者：
M. Fujii;M. Iwasawa;Y. Funato;J. Makino
我们对银河系中心（GC）附近的星星团进行了完全自洽的N体模拟。这种模拟以前没有执行过，因为使用常规方法很难生成这些系统的快速和准确的模拟。我们使用了Bridge代码，该代码使用树算法集成了母星系，并使用具有单独时间步长的四阶Hermite方案集成了星星集群。用树算法计算了母星系与星星团的相互作用。因此，Bridge程序可以同时正确地处理星星团的轨道演化和内部演化。本文利用Bridge程序研究了星星团的演化，并与前人的研究结果进行了比较。我们发现：（1）星星团的内旋时间尺度比“传统的”模拟结果要短，“传统的”模拟是用动力学摩擦公式解析计算星星团的轨道演化;（2）星星团的核心坍缩增加了核心密度，有助于星团的生存。星星团的初始条件并不像以前所认为的那样严格。
We have performed fully self-consistent N-body simulations of star clusters near the Galactic center (GC). Such simulations have not been previously performed, because it is difficult to generate fast and accurate simulations of these systems using conventional methods. We used the Bridge code, which integrates the parent galaxy using a tree algorithm and the star cluster using a fourth-order Hermite scheme with individual time steps. The interaction between the parent galaxy and the star cluster is calculate with a tree algorithm. Therefore, the Bridge code can handle both the orbital and internal evolution of star clusters correctly at the same time. We here investigate the evolution of star clusters using the Bridge code, and compare the results with previous studies. We find that (1) the inspiral timescale of the star clusters is shorter than that obtained with “traditional” simulations, in which the orbital evolution of star clusters is calculated analytically using the dynamical friction formula, and (2) core collapse of the star cluster increases the core density and helps the cluster to survive. The initial conditions of star clusters are not so severe as previously suggested.