The Dependence of Dark Halo Clustering on Formation Epoch and Concentration Parameter
The Dependence of Dark Halo Clustering on Formation Epoch and Concentration Parameter
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DOI：
10.1086/511130
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发表时间：
2006-10
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影响因子：
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通讯作者：
Yipeng Jing;Y. Suto;H. Mo
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文献类型：
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作者：
Yipeng Jing;Y. Suto;H. Mo
我们使用一组7个高分辨率的宇宙学模拟，每个模拟N = 10243个粒子，以前所未有的精度研究了暗物质晕团簇的年龄依赖性。我们使用交叉功率谱方法测量了大质量范围内晕的偏置参数，该方法可以有效地抑制随机噪声，即使在最大质量晕的稀疏采样中也是如此。这使我们第一次发现，对于质量为M > 10M*（其中M*是典型的非线性质量尺度）的晕，年轻的晕比老的晕聚集得更强烈。对于M < M*，我们的结果证实了Gao等人之前的发现，即较老的光晕比较年轻的光晕聚集得更强烈。我们还研究了光晕偏差随光晕浓度的变化规律，发现对于M < M*，光晕偏差的浓度依赖性弱于年龄依赖性，而对于M > 50M*，光晕偏差的浓度依赖性强。对光晕偏差年龄依赖性的精确而可靠的测量指出了简单的漂移集理论的局限性，该理论预测给定质量的光晕的形成和结构与环境无关。
We examine the age dependence of dark matter halo clustering at an unprecedented accuracy using a set of seven high-resolution cosmological simulations, each with N = 10243 particles. We measure the bias parameters for halos over a large mass range using the cross-power-spectrum method that can effectively suppress the random noise, even in the sparse sampling of the most massive halos. This enables us to find, for the first time, that younger halos are more strongly clustered than older ones for halo masses M > 10M*, where M* is the characteristic nonlinear mass scale. For M < M*, our results confirm the previous finding of Gao et al. that older halos are clustered more strongly than the younger ones. We also study the halo bias as a function of halo concentration, and find that the concentration dependence is weaker than the age dependence for M < M*, but stronger for M ≳ 50M*. The accurate and robust measurement of the age dependences of halo bias points to a limitation of the simple excursion-set theory, which predicts that the formation and structure of a halo of given mass is independent of its environment.