ON THE CORES OF COLLISIONLESS SELF-GRAVITATING SYSTEMS

We test a hypothesis that 'the core produced through N-body simulation of a collisionless self-gravitating system is the lowest energy state accessible from the given initial configuration under the constraint of incompressible redistribution of phase-space density.' We construct lowest energy states for Van Albada's uniform initial configurations and compare them with his simulation results. Although there are quantitatively large differences, some qualitative similarities exist in the one-particle energy distribution function N(epsilon) and the density profile rho(r). This fact indicates that the hypothesis holds but rather incompletely for 3D cases, which makes a striking contrast to 1D cases where it seems to hold fairly well. Also we find that the theory of Wiechen, Ziegler & Schindler, for predicting the final state of violent relaxation, is not useful, at least for the core parts of N-body simulations.