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arXiv 0801.1851astro-ph
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无标度宇宙学中的暗物质晕分布

Dark Matter Halo Profiles in Scale-Free Cosmologies

Steffen R. Knollmann, Chris Power, Alexander Knebe

摘要:

我们探索的中心对数斜率的暗物质晕密度剖面$α$的线性物质功率谱$P(k)$的光谱指数$n$的依赖关系,使用宇宙学$N$体模拟的无标度模型(即$P(k) \propto k^n$)。对于我们的每一个模拟,我们确定样本的动态平衡以及解决晕,我们分析他们的质量档案。通过参数化的质量配置文件使用"广义“纳瓦罗,弗伦克和白色的配置文件,其中的中心对数斜率$α$允许变化,同时保持$r^{-3}$渐近形式在大半径,我们获得首选的中心斜率晕在我们的每个模型。在$α$和$n$之间存在强相关性,使得当$n$变得更陡时,$α$变得更浅。然而,如果我们用$r_{-2}$(密度曲线的对数斜率为-2的半径)对质量曲线进行归一化,我们发现这些差异不再存在。我们的结论是,没有证据表明收敛到一个独特的中央渐近斜率,至少在规模,我们可以解决。

英文摘要:

We explore the dependence of the central logarithmic slope of dark matter halo density profiles $α$ on the spectral index $n$ of the linear matter power spectrum $P(k)$ using cosmological $N$-body simulations of scale-free models (i.e. $P(k) \propto k^n$). For each of our simulations we identify samples of well resolved haloes in dynamical equilibrium and we analyse their mass profiles. By parameterising the mass profile using a ``generalised'' Navarro, Frenk & White profile in which the central logarithmic slope $α$ is allowed to vary while preserving the $r^{-3}$ asymptotic form at large radii, we obtain preferred central slopes for haloes in each of our models. There is a strong correlation between $α$ and $n$, such that $α$ becomes shallower as $n$ becomes steeper. However, if we normalise our mass profiles by $r_{-2}$, the radius at which the logarithmic slope of the density profile is -2, we find that these differences are no longer present. We conclude that there is no evidence for convergence to a unique central asymptotic slope, at least on the scales that we can resolve.

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