How Dark Matter Halos Cluster in Lagrangian Space
How Dark Matter Halos Cluster in Lagrangian Space
复制标题
拉格朗日空间中的暗物质晕如何聚集
DOI：
--
复制
发表时间：
1998
期刊：
影响因子：
--
通讯作者：
C. Lacey
中科院分区：
文献类型：
--
作者：
C. Porciani;P. Catelan;C. Lacey
我们研究了暗物质晕在拉格朗日空间中的两点相关函数的聚类。分析一组无碰撞无标度的1283粒子N体模拟的光谱指数n=-2，-1，我们测量的前两个拉格朗日偏置参数b1和b2晕和质量相关。我们发现，Mo &白色的b1首阶公式相当准确地描述了质量为M M（其中M表示特征非线性质量）的晕簇。较小的晕在拉格朗日空间中的聚集性比Mo和白色预测的要小。我们的研究结果与Jing最近在欧拉空间中对晕族的聚类结果一致，表明N体和分析Mo &白色预测之间的偏差在拉格朗日空间中已经存在。这表明，需要开发一种在初始条件下选择晕的更精确的理论算法。最后，我们给出了拉格朗日空间中线性晕偏因子b1的一个非常精确的拟合公式。
We investigate the clustering of dark matter halos in Lagrangian space in terms of their two-point correlation function. Analyzing a set of collisionless scale-free 1283 particle N-body simulations with spectral indices n=-2, -1, we measure the first two Lagrangian bias parameters b1 and b2 relating halo and mass correlations. We find that the Mo & White leading-order formula for b1 describes the clustering of halos with mass M≳M (where M⋆ indicates the characteristic nonlinear mass) quite accurately. Smaller halos turn out to be less clustered in Lagrangian space than predicted by Mo & White. Our findings are consistent with the recent results of Jing for the clustering of halo populations in Eulerian space, demonstrating that the discrepancies between the N-body and analytical Mo & White prediction for the bias exist already in Lagrangian space. This shows that a more refined theoretical algorithm for selecting halos in the initial conditions needs to be developed. Finally, we present a very accurate fitting formula for the linear halo bias factor b1 in Lagrangian space.