1998/11/23 by Takashi Okamoto, T. Okamoto, Asao Habe +1 · 4 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/307126
published as Astrophys.J.516:591-603,1999 · 20 pages, 14 Postscript figures, uses AASTeX, accepted for publication in ApJ
arxiv created 1998/11/23 · openalex publication_date 1999/05/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We investigate effects of time evolution of a rich cluster of galaxies on its member galactic halos in the standard cold dark matter (SCDM) universe using high resolution N -body simulations. We identify several hundred galactic halos within the virial radius of our simulated cluster. We also find that a large number of halos have been tidally disrupted at z =0. Therefore we improve a method of deriving merging history trees of galaxies taking account of tidally stripped galaxies. The main results are as follows: (1) At high redshift ( z ≃2), the mass function of the galactic halos that are in the cluster at z =0 is very similar to that obtained in the field region and agrees well with the Press-Schechter mass function. (2) The mass function of cluster galaxies that consist of both galactic halos and tidally stripped galaxies has hardly evolved since z ≃2. This mass function at z =0 is well represented by the Press-Schechter mass function at z =2. (3) At high redshift ( z >3), in the region that becomes the cluster, the fraction of galaxies that have undergone recent merger is larger than that in the field. After z ~3, however, it rapidly decreases and becomes smaller than that in the field. (4) The fraction of strongly stripped galaxies among the cluster galaxies begins to increase from z ≃0.5. At z =0, a clear correlation appears between this fraction and the distance from the center of the cluster. (5) Tidally truncated halos have steeper outer profiles than those of the model of Navarro, Frenk, & White.