2003/05/31 by H. J. de Vega, Julien Siebert, J. A. Siebert · 2 citations
Physics and Astronomy · #Cosmology and Gravitation Theories #Relativity and Gravitational Theory #Statistical Mechanics and Entropy #astro-ph #cond-mat #gr-qc #hep-th
paper · pdf · doi:10.1016/j.nuclphysb.2004.11.013
published as Nucl.Phys. B707 (2005) 529-552 · LaTex, 29 pages, 15 .ps figures. Stability analysis revised and improved
arxiv created 2003/10/31 · openalex publication_date 2004/12/14 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The non-relativistic self-gravitating gas in thermal equilibrium in the presence of a positive cosmological constant Lambda (dark energy) is investigated. The dark energy introduces a force pushing outward all particles with strength proportional to their distance to the center of mass.We consider the statistical mechanics of the self-gravitating gas of N particles in a volume V at thermal equilibrium in the presence of Lambda. It is shown that the thermodynamic limit exists and is described by the mean field equations provided N, V -> inf with N/V1/3 fixed and Lambda V2/3 fixed. That is, Lambda -> 0 for N, V -> inf. The case of Lambda fixed and N, V -> inf is solved too. We solve numerically the mean field equation for spherical symmetry obtaining an isothermal sphere for Lambda>0. The particle distribution turns to flatten compared with the Lambda = 0 case.Moreover, the particle density increases with the distance when the cosmological constant dominates. There is a bordering case with uniform density.The density contrast between the center and the boundary is significatively reduced. In addition, the critical point associated to the collapse (Jeans') phase transition is pushed towards higher values of N/[T V1/3] by the presence of Lambda > 0.The nature and the behaviour near the critical points is not affected by the presence of Lambda>0.