Environmental dependence of dark matter halo growth - I. Halo merger rates

2008/08/31 by Onsi Fakhouri, Chung-Pei Ma, Chung‐Pei Ma · 135 citations
Physics and Astronomy · #Adaptive optics and wavefront sensing #Amplitude #Astronomy and Astrophysical Research #Astrophysics #Cosmology #Dark matter #Dark matter halo #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Halo #Halo mass function #Physics #Redshift #astro-ph

paper · pdf · doi:10.1111/j.1365-2966.2009.14480.x

published in Monthly Notices of the Royal Astronomical Society 394(4), 1825-1840 (Oxford University Press) · 14 pages, 8 figures, Moderate revisions in version 2. Accepted in MNRAS

arxiv created 2009/01/23 · openalex publication_date 2009/03/16 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

In an earlier paper, we quantified the mean merger rate of dark matter haloes as a function of redshift z, descendant halo mass M0, and progenitor halo mass ratio ξ using the Millennium simulation of the Λ cold dark matter cosmology. Here, we broaden that study and investigate the dependence of the merger rate of haloes on their surrounding environment. A number of local mass overdensity variables, both including and excluding the halo mass itself, are tested as measures of a halo's environment. The simple functional dependence on z, M0, and ξ of the merger rate found in our earlier work, is largely preserved in different environments, but we find that the overall amplitude of the merger rate has a strong positive correlation with the environmental densities. For galaxy-mass haloes, we find mergers to occur ∼2.5 times more frequently in the densest regions than in voids at both z= 0 and higher redshifts. Higher mass haloes show similar trends. We present a fitting form for this environmental dependence that is a function of both mass and local density and valid out to z= 2. The amplitude of the progenitor (or conditional) mass function shows a similar correlation with local overdensity, suggesting that the extended Press–Schechter model for halo growth needs to be modified to incorporate environmental effects.

Citations

• THE EXCURSION SET THEORY OF HALO MASS FUNCTIONS, HALO CLUSTERING, AND HALO GROWTH
• The mass of a halo
• A primer on hierarchical galaxy formation: the semi-analytical approach
• The spin and shape of dark matter haloes in the Millennium simulation of a Λ cold dark matter universe
• Assembly bias in the clustering of dark matter haloes
• Why does the clustering of haloes depend on their formation history?
• Simulations of the formation, evolution and clustering of galaxies and quasars
• Toward a Halo Mass Function for Precision Cosmology: The Limits of Universality
• On the environmental dependence of halo formation

Cited by

• Mass accretion rates and multi-scale halo environment in cold and warm dark matter cosmologies
• A machine learning approach to galaxy–LSS classification – I. Imprints on halo merger trees
• THE GROWTH OF DARK MATTER HALOS: EVIDENCE FOR SIGNIFICANT SMOOTH ACCRETION