Evolution of the Phase-Space Density of Dark Matter Halos and Mixing Effects in Merger Events

Abstract

Cosmological N-body simulations were performed to study the evolution of the phase-space density Q = rho/sigma^3 of dark matter halos. No significant differences in the scale relations Q ~ sigma^(-2.1) or Q ~ M^(-0.82) are seen for "cold" or "warm" dark matter models. The follow up of individual halos from z = 10 up to the present time indicate the existence of two main evolutionary phases: an early and fast one (10 > z > 6.5), in which Q decreases on the average by a factor of 40 as a consequence of the randomization of bulk motions and a late and long one (6.5 > z > 0), in which Q decreases by a factor of 20 because of mixing induced by merger events. The study of these halos has also evidenced that rapid and positive variations of the velocity dispersion, induced by merger episods, are related to a fast decrease of the phase density Q.

6 pages, accepted by MNRAS

References in corpus (8)

• The 2dF Galaxy Redshift Survey: Power-spectrum analysis of the final dataset and cosmological implications
• The cored distribution of dark matter in spiral galaxies
• The Gemini Deep Deep Survey: III. The abundance of massive galaxies 3-6 billion years after the Big Bang
• Inferring the dark matter power spectrum from the Lyman-alpha forest in high-resolution QSO absorption spectra
• A dynamical model for the distribution of dark matter and gas in galaxy clusters
• The angular momentum of dark halos: merger and accretion effects
• Dark energy effects on the Lyman-alpha forest
• Entropy of gravitationally collapsing matter in FRW universe models

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