A collisional N-body simulation using NBODY5 on a single CRAY YMP processor is followed well into the post-collapse regime. This is presently one of the largest particle numbers of all such models published, but some data for an even larger N produced by using special-purpose computers have recently been presented. In contrast to previous ensemble-averaged N-body simulations the noise here is low enough just to compare this one single run with the expectations from statistical models based on the Fokker-Planck approximation. Agreement is as good as could be expected for the case of the evolution of the Lagrangian radii, radial and tangential velocity dispersions and various core quantities. We discuss briefly approximate models to understand the number and the energy of escapers and the question of gravothermal core oscillations; although the system exhibits post-collapse oscillations they turn out to be directly binary driven and we cannot prove the existence of a gravothermal expansion at this particle number. Finally in a detailed examination of the wandering of the density centre we find, in contrast to some previous studies, a clear long-time period of the order of approximately 14 half-mass crossing times.
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- September 1996
- 13 pages, Blackwell publishers Macro mn.tex for MNRAS used, tex-source without figures, full ps.gz available through http://www.astrophysik.uni-kiel.de/papers/d-spurzem_07_12_95.html (click on: Postscript-File (1.1 MB) ), in press for MNRAS