1998/07/28 by Rachel S. Somerville, Gerard Lemson, Tsafrir Kolatt +2 · 7 citations
Environmental Science · Physics and Astronomy · #Galaxies: Formation, Evolution, Phenomena #Remote Sensing and LiDAR Applications #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.2000.03467.x
published as Mon.Not.Roy.Astron.Soc. 316 (2000) 479 · 10 pages including 9 figures, submitted to MNRAS
arxiv created 1998/07/28 · openalex publication_date 2000/08/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
We study the merging history of dark matter haloes in N-body simulations and semi-analytical ‘merger trees’ based on the extended Press-Schechter (EPS) formalism. The main focus of our study is the joint distribution of progenitor number and mass as a function of redshift and parent halo mass. We begin by investigating the mean quantities predicted directly by the Press-Schechter (PS) and EPS formalism, such as the halo mass and conditional mass functions, and compare these predictions with the results of the simulations. The higher moments of this distribution are not predicted by the EPS formalism alone and must be obtained from the merger trees. We find that the Press-Schechter model deviates from the simulations at the level of 30–50 per cent on certain mass scales, and that the sense of the discrepancy changes as a function of redshift. We show that this discrepancy is reflected in the higher moments of the distribution of progenitor mass and number. We investigate some related statistics such as the accretion rate and the mass ratio of the largest two progenitors. For galaxy sized haloes (M∼1012 M⊙), we find that the merging history of haloes, as represented by these statistics, is well reproduced in the merger trees compared with the simulations. The agreement deteriorates for larger mass haloes. We conclude that merger trees based on the extended Press-Schechter formalism provide a reasonably reliable framework for semi-analytical models of galaxy formation.