Clustering of galaxies in a hierarchical universe - I. Methods and results at z=0

摘要: We introduce a new technique for following the formation and evolution of galaxies in cosmological N-body simulations. Dissipationless simulations are used to track merging dark matter haloes as function redshift. Simple prescriptions, taken directly from semi-analytic models galaxy formation, adopted gas cooling, star supernova feedback within haloes. This scheme enables us explore clustering properties galaxies, investigate how selection by luminosity, colour or type influences results. In this paper we study distribution at z=0. These include B- K-band luminosity functions, two-point correlation pairwise peculiar velocities, cluster mass-to-light ratios, B-V colours, rates. focus on two variants cold (CDM) cosmology: high-density (Ω =1) model with shape-parameter Γ =0.21 (τ CDM), low-density Ω =0.3 Λ =0.7 (Λ CDM). Both normalized reproduce I-band Tully--Fisher relation Giovanelli et al. near circular velocity 220 km s-1. Our results depend strongly both normalization prescriptions feedback. Very different assumptions required obtain an acceptable cases. For τ CDM, efficient is suppress growth particularly low-mass field Without it, there too many exhibits strong turnover scales below 1 Mpc. must be weaker, otherwise few L* produced steep. Although neither perfect, come close reproducing most data. Given uncertainties modelling some critical physical processes, conclude that it not yet possible draw firm conclusions about values parameters studies kind. Further observational work global effects narrow range possibilities.