2008/08/21 by Yan Levin, Renato Pakter, Felipe B. Rizzato +1 · 2 citations
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Astrophysics #Classical mechanics #Cosmology and Gravitation Theories #Distribution function #Gravitation #Gravitational collapse #Gravitational energy #Gravitational potential #Mass distribution #Mechanics #Metastability #Physics #Potential energy #Quantum mechanics #Relaxation (psychology) #Smoothed-particle hydrodynamics #Statistical Mechanics and Entropy #Thermodynamics #Virial theorem #astro-ph #cond-mat.other #cond-mat.stat-mech
paper · pdf · doi:10.1103/physreve.78.021130
published as Phys. Rev. E 78, 021130 (2008)
openalex publication_date 2008/08/21 · arxiv created 2008/08/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Theory and simulations are used to study collisionless relaxation of a gravitational N -body system. It is shown that when the initial one-particle distribution function satisfies the virial condition--potential energy is minus twice the kinetic energy--the system quickly relaxes to a metastable state described quantitatively by the Lynden-Bell distribution with a cutoff. If the initial distribution function does not meet the virial requirement, the system undergoes violent oscillations, resulting in a partial evaporation of mass. The leftover particles phase-separate into a core-halo structure. The theory presented allows us to quantitatively predict the amount and the distribution of mass left in the central core, without any adjustable parameters. On a longer time scale tauG-N , collisionless relaxation leads to a gravothermal collapse.