2003/08/31 by Pedro Colín, P. Colin, A. Klypin +4 · 2 citations
Physics and Astronomy · #Astronomy #Astrophysics #Dark Matter and Cosmic Phenomena #Dark matter #Dark matter halo #Dwarf galaxy problem #Galaxies: Formation, Evolution, Phenomena #Galaxy #Halo #Milky Way #Physics #Redshift #Scientific Research and Discoveries #astro-ph
paper · pdf · doi:10.1086/422463
published as Astrophys.J.612:50-57,2004 · Accepted to be pusblished by ApJ, 12 pages, 8 figures, LaTeX (documentclass preprint2). Differences with respect to the previous submission are: (i) abstract was modified slightly to make it more transparent to the reader, (ii) an extra figure has been added, and (3) some minor modifications to the main text were also done
arxiv created 2004/05/11 · openalex publication_date 2004/09/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study properties of dark matter halos at high redshifts z = 2-10 for a vast range of masses with the emphasis on dwarf halos with masses of 10 7 -10 9 h -1 M ☉ . We find that the density profiles of relaxed dwarf halos are well fitted by the Navarro, Frenk, & White (NFW) profile and do not have cores . We compute the halo mass function and the halo spin parameter distribution and find that the former is very well reproduced by the Sheth & Tormen model, while the latter is well fitted by a lognormal distribution with λ 0 = 0.042 and σ λ = 0.63. We estimate the distribution of concentrations for halos in a mass range that covers 6 orders of magnitude, from 10 7 to 10 13 h -1 M ☉ , and find that the data are well reproduced by the model of Bullock et al. The extrapolation of our results to z = 0 predicts that present-day isolated dwarf halos should have a very large median concentration of ~35. We measure the subhalo circular velocity functions for halos with masses that range from 4.6 × 10 9 to 10 13 h -1 M ☉ and find that they are similar when normalized to the circular velocity of the parent halo. Dwarf halos studied in this paper are many orders of magnitude smaller than well-studied cluster- and Milky Way-sized halos. Yet, in all respects the dwarfs are just downscaled versions of the large halos. They are cuspy and, as expected, more concentrated. They have the same spin parameter distribution and follow the same mass function that was measured for large halos.