Triaxial Modeling of Halo Density Profiles with High-Resolution N-Body Simulations
Triaxial Modeling of Halo Density Profiles with High-Resolution N-Body Simulations
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DOI：
10.1086/341065
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发表时间：
2002-02
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影响因子：
--
通讯作者：
Y. Jing;Y. Suto
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文献类型：
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作者：
Y. Jing;Y. Suto
我们在对高分辨率晕模拟（12个晕，在其维里半径内有\(N\approx10^{6}\)个粒子）和大型宇宙学模拟（在\(100h^{-1}\)百万秒差距盒子大小中有\(N = 512^{3}\)个粒子的五种实现）进行综合分析的基础上，提出了暗物质晕的详细非球对称建模。这些模拟晕的密度剖面可以通过一系列同心三轴分布很好地近似，其轴方向相当对齐。我们通过推广通用密度剖面（之前仅在球对称模型框架内讨论过）对三轴模型进行定量表征。在应用三轴模型时，我们得到了一系列实用的拟合公式：轴比的质量和红移依赖性、浓度参数的平均值以及轴比和浓度参数的概率分布函数。这些精确的拟合公式完整地描述了冷暗物质模型中晕的三轴密度剖面。我们目前对暗晕的描述在合理可靠的程度上预测各种非球对称效应将特别有用，包括弱透镜和强透镜统计、星系卫星的轨道演化和星系晕的三轴性以及暗物质的非线性聚类。此外，这为星系团内气体的非球对称建模提供了一个有用的框架，这对于讨论X射线星系团的气体和温度剖面以及通过苏尼亚耶夫 - 泽尔多维奇效应估计哈勃常数至关重要。
We present a detailed nonspherical modeling of dark matter halos on the basis of a combined analysis of high-resolution halo simulations (12 halos with N ~ 106 particles within their virial radius) and large cosmological simulations (five realizations with N = 5123 particles in a 100 h-1 Mpc box size). The density profiles of those simulated halos are well approximated by a sequence of the concentric triaxial distribution with their axis directions being fairly aligned. We characterize the triaxial model quantitatively by generalizing the universal density profile, that has previously been discussed only in the framework of the spherical model. We obtain a series of practically useful fitting formulae in applying the triaxial model: the mass and redshift dependence of the axis ratio, the mean of the concentration parameter, and the probability distribution functions of the axis ratio and the concentration parameter. These accurate fitting formulae form a complete description of the triaxial density profiles of halos in cold dark matter models. Our current description of the dark halos will be particularly useful in predicting a variety of nonsphericity effects, to a reasonably reliable degree, including the weak and strong lens statistics, the orbital evolution of galactic satellites and triaxiality of galactic halos, and the nonlinear clustering of dark matter. In addition, this provides a useful framework for the nonspherical modeling of the intracluster gas, which is crucial in discussing the gas and temperature profiles of X-ray clusters and the Hubble constant estimated via the Sunyaev-Zeldovich effect.