Accurate universal models for the mass accretion histories and concentrations of dark matter halos
Nov, 2008Citations per year
Abstract: (arXiv)
We use a large set of high-resolution N-body simulations of a variety of structure formation models (scale-free, Lambda CDM, standard CDM, and open CDM) to study the mass accretion histories, the mass- and redshift-dependence of concentrations and the concentration evolution histories of dark matter halos. We show that the much-used empirical models in the literature all fail significantly to match our simulations. Based on our simulation results, we find that the mass accretion rate of a halo is tightly correlated with a combination of its mass, the redshift, parameters of the cosmology and the initial density fluctuation. We also find that the concentration of a halo is strongly correlated with the universe age when its progenitor on the mass accretion history first reaches 4% of its current mass. According to these correlations, we develop new empirical models for both the mass accretion histories and the concentration evolution histories of dark matter halos, and the latter can also be used to predict the mass- and redshift-dependence of halo concentrations. These models are accurate and universal: the same set of model parameters works well for different cosmological models and for halos of different masses at different redshifts. These models are also simple and easy to implement. We provide an appendix describing the step-by-step implementation of our models. A calculator which allows one to interactively generate data for any given cosmological model is provided at http://www.shao.ac.cn/dhzhao/mandc.html, together with a user-friendly code to make the relevant calculations and some tables listing the expected concentration as a function of halo mass and redshift in several popular cosmological models.References(23)
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