A study of relative velocity statistics in Lagrangian perturbation theory with PINOCCHIO
A study of relative velocity statistics in Lagrangian perturbation theory with PINOCCHIO
复制标题
用PINOCCHIO研究拉格朗日微扰理论中的相对速度统计
DOI：
10.1111/j.1365-2966.2011.19252.x
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发表时间：
2010
影响因子：
4.8
通讯作者：
M. Bartelmann
中科院分区：
文献类型：
--
作者：
Lavinia Heisenberg;B. Schaefer;M. Bartelmann
本文详细分析了拉格朗日微扰理论中用于研究并合晕相对速度统计特性的PINpointing-Orbit-Crossing Collapsed Higerical Object（PINOCCHIO）算法。给定一个宇宙学背景模型，在立方网格上产生涨落的功率谱和高斯线性密度衬度场δl，然后用高斯滤波器反复平滑。对于每个拉格朗日粒子在位置q和每个平滑半径R，崩溃时间，速度和椭球截断计算使用拉格朗日摄动理论。然后，通过一种旨在模拟分层塌陷的吸积和合并事件的算法，塌陷的介质被分割成孤立的对象。直接在碎裂过程的质量函数，合并历史的晕和合并时的相对速度的统计数据进行评估。我们在C++中重新实现了该算法，恢复了质量函数，并优化了Halo合并历史的构造。当与千年模拟的输出相比，我们的结果表明，PINOCCHIO是非常适合于研究合并晕的相对速度，并能够再现成对的速度分布。
Subject of this paper is a detailed analysis of the PINpointing Orbit-Crossing Collapsed HIerarchical Object (PINOCCHIO) algorithm for studying the relative velocity statistics of merging haloes in Lagrangian perturbation theory. Given a cosmological background model, a power spectrum of fluctuations as well as a Gaussian linear density contrast field δl is generated on a cubic grid, which is then smoothed repeatedly with Gaussian filters. For each Lagrangian particle at position q and each smoothing radius R, the collapse time, the velocities and ellipsoidal truncation are computed using Lagrangian perturbation theory. The collapsed medium is then fragmented into isolated objects by an algorithm designed to mimic the accretion and merger events of hierarchical collapse. Directly after the fragmentation process the mass function, merger histories of haloes and the statistics of the relative velocities at merging are evaluated. We reimplemented the algorithm in C++, recovered the mass function and optimized the construction of halo merging histories. When compared with the output of the Millennium Simulation our results suggest that the PINOCCHIO is well suited for studying relative velocities of merging haloes and is able to reproduce the pairwise velocity distribution.
影响因子：
64.8
作者：
Springel, V;White, SDM;Pearce, F
通讯作者：
Pearce, F