The ecology of dark matter haloes I: The rates and types of halo interactions

Abstract

Interactions such as mergers and flybys play a fundamental role in shaping galaxy morphology. Using the Horizon Run 4 cosmological N-body simulation, we studied the frequency and type of halo interactions, and their redshift evolution as a function of the environment defined by the large-scale density, pair separation, mass ratio, and target halo mass. Most interactions happen at large-scale density contrast $\delta \approx 20$, regardless of the redshift, corresponding to groups and relatively dense part of filaments. However, the fraction of interacting target is maximum at $\delta \approx 1000$. We provide a new empirical fitting form for the interaction rate as a function of the halo mass, large-scale density, and redshift. We also report the existence of two modes of interactions from the distributions of mass ratio and relative distance, implying two different physical origins of the interaction. Satellite targets lose their mass as they proceed deeper into the host halo. The relative importance of these two trends strongly depends on the large-scale density, target mass, and redshift.

Accepted for publication in MNRAS. 13 pages, 13 figures

References in corpus (14)

• The merger rate of galaxies in the Illustris Simulation: a comparison with observations and semi-empirical models
• Galaxy Zoo 1 : Data Release of Morphological Classifications for nearly 900,000 galaxies
• Star formation efficiency in galaxy interactions and mergers: a statistical study
• The Nearly Universal Merger Rate of Dark Matter Haloes in Lambda-CDM Cosmology
• Galaxy And Mass Assembly (GAMA): Galaxy close-pairs, mergers, and the future fate of stellar mass
• The growth of dark matter halos: evidence for significant smooth accretion
• Environmental Dependence of Dark Matter Halo Growth I: Halo Merger Rates
• Satellites of Simulated Galaxies: survival, merging, and their relation to the dark and stellar halos
• Transformation of Morphology and Luminosity Classes of the SDSS Galaxies
• The rise and fall of stellar discs across the peak of cosmic star formation history: mergers versus smooth accretion
• The ALHAMBRA survey: Accurate merger fractions by PDF analysis of photometric close pairs
• Evidence for Morphology and Luminosity Transformation of Galaxies at High Redshifts
• Evolution of the Major Merger Galaxy Pair Fraction at z < 1
• Halo mass distribution reconstruction across the cosmic web

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• On the Effects of Local Environment on Active Galactic Nucleus (AGN) in the Horizon Run 5 Simulation
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• Hermeian haloes: extreme objects with two interactions in the past
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