Pairwise Velocity Statistics of Dark Halos
We have accurately evaluated the halo pairwise velocity dispersion and the halo mean streaming velocity in the LCDM model (the flat ω0 = 0.3 model)using a set of high-resolution N-body simulations. Based on the simulation results,we have developed a model for the pairwise velocity dispersion of halos. Our model agrees with the simulation results over all scales we studied. We have also tested the model of Sheth et al. for the mean streaming motion of halos derived from the pair-conservation equation. We found that their model reproduces the simulation data very well on large scale, but under-predicts the streaming motion on scales r ＜ 10 h-1 Mpc. We have introduced an empirical relation to improve their model.These improved models are useful for predicting the redshift correlation functions and the redshift power spectrum of galaxies if the halo occupation number model,e.g. the cluster weighted model, is given for the galaxies.
作 者： Hai-Yan Zhang Yi-Peng Jing 作者单位： Hai-Yan Zhang(Department of Astronomy, Peking University, Beijing,100871)Yi-Peng Jing(Shanghai Astronomy Observatory, the Partner Group of MPI für Astrophysik,Nandan Road 80, Shanghai, 200030)
刊 名： 天体物理学报（英文版） ISTIC SCI 英文刊名： CHINESE JOURNAL OF ASTRONOMY AND ASTROPHYSICS 年，卷(期)： 2004 4(6) 分类号： P14 关键词： cosmology: theory - dark matter halo - large-scale structure of universe