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A universal density slope – velocity anisotropy relation
Published online by Cambridge University Press: 19 May 2006
Abstract
One can solve the Jeans equation analytically for equilibrated dark matter structures, once given two pieces of input from numerical simulations. These inputs are 1) a connection between phase-space density and radius, and 2) a connection between velocity anisotropy and density slope, the α – β relation. The first (phase-space density vs. radius) has been analysed through several different simulations, however the second (α – β relation) has not been quantified yet. We perform a large set of numerical experiments in order to quantify the slope and zero-point of the α – β relation. This allows us to conclude that equilibrated dark matter structures indeed have zero central velocity anisotropy, central density slope of α0 ≈ –0.8, and outer anisotropy of approximately β∞ ≈ 0.5.
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- © EAS, EDP Sciences, 2006
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