Author:
Halle A.,Colombi S.,Peirani S.
Abstract
In the mean field limit, isolated gravitational systems often evolve towards a steady state through a violent relaxation phase. One question is to understand the nature of this relaxation phase, in particular the role of radial instabilities in the establishment/destruction of the steady profile. Here, through a detailed phase-space analysis based both on a spherical Vlasov solver, a shell code, and a N-body code, we revisit the evolution of collisionless self-gravitating spherical systems with initial power-law density profiles ρ(r) ∝ rn, 0 ≤ n ≤ −1.5, and Gaussian velocity dispersion. Two sub-classes of models are considered, with initial virial ratios η = 0.5 (“warm”) and η = 0.1 (“cool”). Thanks to the numerical techniques used and the high resolution of the simulations, our numerical analyses are able, for the first time, to show the clear separation between two or three well-known dynamical phases: (i) the establishment of a spherical quasi-steady state through a violent relaxation phase during which the phase-space density displays a smooth spiral structure presenting a morphology consistent with predictions from self-similar dynamics, (ii) a quasi-steady-state phase during which radial instabilities can take place at small scales and destroy the spiral structure but do not change quantitatively the properties of the phase-space distribution at the coarse grained level, and (iii) relaxation to a non-spherical state due to radial orbit instabilities for n ≤ −1 in the cool case.
Funder
Agence Nationale de la Recherche
Yukawa Institute for Theoretical Physics, Kyoto University
Subject
Space and Planetary Science,Astronomy and Astrophysics
Cited by
5 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献