2006/10/05 by Eric I. Barnes, Liliya L. R. Williams, Arif Babul +1
Mathematics · Physics and Astronomy · #Astrophysics #Classical mechanics #Cosmology and Gravitation Theories #Dark matter #Distribution (mathematics) #Galaxies: Formation, Evolution, Phenomena #Mathematical analysis #Mathematics #Monotonic function #Physics #Polytropic process #Statistical Mechanics and Entropy #Statistical physics #Theoretical physics #Thermodynamics #Work (physics) #astro-ph
paper · pdf · doi:10.1086/509871
published as Astrophys.J.655:847-850,2007 · 3 color figures, accepted for publication in ApJ
arxiv created 2006/10/05 · openalex publication_date 2007/01/23 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
There is no accepted mechanism that explains the equilibrium structures that form in collisionless cosmological N -body simulations. Recent work has identified nonextensive thermodynamics as an innovative approach to the problem. The distribution function that results from adopting this framework has the same form as for polytropes, but the polytropic index is now related to the degree of nonextensiveness. In particular, the nonextensive approach can mimic the equilibrium structure of dark matter density profiles found in simulations. We extend the investigation of this approach to the velocity structures expected from nonextensive thermodynamics. We find that the nonextensive and simulated N -body v rms distributions do not match one another. The nonextensive v rms profile is either monotonically decreasing or displays little radial variation, each of which disagrees with the v rms distributions seen in simulations. We conclude that the currently discussed nonextensive models require further modifications in order to corroborate dark matter halo simulations.