Stirring N-body systems: Universality of end states

Abstract

We study the evolution of the phase space of collisionless N-body systems under repeated stirrings or perturbations. We find convergence towards a limited solution group, in accordance with Hansen, Juncher & Sparre, that is independent of the initial system and environmental conditions, paying particular attention to the assumed gravitational paradigm (Newtonian and Modified Newtonian Dynamics). We examine the effects of changes to the perturbation scheme and in doing so identify a large group of perturbations featuring radial orbit instability which always lead to convergence. The attractor is thus found to be a robust and reproducible effect under a variety of circumstances. © 2012 The Authors. Monthly Notices of the Royal Astronomical Society © 2012 RAS.