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arXiv 1808.03088astro-ph.GAastro-ph.COgr-qc
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暗物质晕的中心尖点:事实还是虚构?

The central cusps in dark matter halos: fact or fiction?

A. N. Baushev, S. V. Pilipenko

摘要:

我们调查的可靠性标准N体模拟的建模著名的Hernquist晕的帮助下,\texttt{GADGET-2}代码(使用树算法来计算引力)和\texttt{ph4}代码(使用直接求和)。比较结果,我们发现,在晕中心的核心形成(这是传统上被认为是第一个数字效应的迹象,具体来说,碰撞松弛)没有任何关系的碰撞松弛,被定义的树算法的属性。这一结果对目前普遍采用的晕心模拟可靠性标准提出了质疑。虽然我们使用的晕模型,这是理论上证明是平稳和稳定的,一种数值的“暴力松弛”发生。它的性质表明,这种效应很可能是负责中央尖点的形成,在宇宙学建模的大尺度结构,然后“核心尖点问题”只是一个技术问题的N体模拟。

英文摘要:

We investigate the reliability of standard N-body simulations by modelling of the well-known Hernquist halo with the help of \texttt{GADGET-2} code (which uses the tree algorithm to calculate the gravitational force) and \texttt{ph4} code (which uses the direct summation). Comparing the results, we find that the core formation in the halo center (which is conventionally considered as the first sign of numerical effects, to be specific, of the collisional relaxation) has nothing to do with the collisional relaxation, being defined by the properties of the tree algorithm. This result casts doubts on the universally adopted criteria of the simulation reliability in the halo center. Though we use a halo model, which is theoretically proved to be stationary and stable, a sort of numerical 'violent relaxation' occurs. Its properties suggest that this effect is highly likely responsible for the central cusp formation in cosmological modelling of the large-scale structure, and then the 'core-cusp problem' is no more than a technical problem of N-body simulations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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