A universal velocity distribution of relaxed collisionless structures

Abstract

Several general trends have been identified for equilibrated, self-gravitating collisionless systems, such as density or anisotropy profiles. These are integrated quantities which naturally depend on the underlying velocity distribution function (VDF) of the system. We study this VDF through a set of numerical simulations, which allow us to extract both the radial and the tangential VDF. We find that the shape of the VDF is universal, in the sense that it depends only on two things namely the dispersion (radial or tangential) and the local slope of the density. Both the radial and the tangential VDF's are universal for a collection of simulations, including controlled collisions with very different initial conditions, radial infall simulation, and structures formed in cosmological simulations.

13 pages, 6 figures; oversimplified analysis corrected; changed abstract and conclusions; significantly extended discussion

References in corpus (14)

• The Structure of Cold Dark Matter Halos
• Resolving the Structure of Cold Dark Matter Halos
• The Structure of Dark Matter Haloes in Hierarchical Clustering Models
• Velocity and spatial biases in CDM subhalo distributions
• The Phase-Space Density Profiles of Cold Dark Matter Halos
• A dynamical model for the distribution of dark matter and gas in galaxy clusters
• The Average Mass Profile of Galaxy Clusters
• Convergence and scatter of cluster density profiles
• Generating Equilibrium Dark Matter Halos: Inadequacies of the Local Maxwellian Approximation
• On the physical origin of dark matter density profiles
• Dark matter in Draco and the Local Group: Implications for direct detection experiments
• Dark matter distribution function from non-extensive statistical mechanics
• Radial velocity moments of dark matter haloes
• Dark matter density profiles from the Jeans equation

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