2008/03/31 by Ding Ma, DING MA, Ping He +1
Physics and Astronomy · #Anisotropy #Astronomy and Astrophysical Research #Constant (computer programming) #Dark Matter and Cosmic Phenomena #Dark matter #Dark matter halo #Distribution (mathematics) #Distribution function #Function (biology) #Galaxies: Formation, Evolution, Phenomena #Halo #astro-ph
paper · pdf · doi:10.1142/s0218271808012826
published as Int.J.Mod.Phys.D17:1283-1294,2008 · 11 pages, accepted for publication in Int. J. Mod. Phys. D, add a quotation
arxiv created 2008/08/01 · openalex publication_date 2008/08/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
N-body simulations of dark matter halos show that the density is cusped near the center of the halo. The density profile behaves as r –γ in the inner parts, where γ ≃ 1 for the NFW model and γ ≃ 1.5 for the Moore model, but in the outer parts the two models agree with each other in the asymptotic behavior of the density profile. The simulations also show information about the anisotropy parameter β(r) of the velocity distribution: β ≈ 0 in the inner part and β ≈ 0.5 (radially anisotropic) in the outer part of the halo. We provide some distribution functions F(E, L) with the constant anisotropy parameter β for the two spherical models of dark matter halos: a new generalized NFW model and a generalized Moore model. There are two parameters α and ∊ for those two generalized models to determine the asymptotic behavior of the density profile. In this paper, we concentrate on the situation of β(r) = 1/2 from the viewpoint of the simulation.