STATISTICS OF N-BODY SIMULATIONS .1. EQUAL MASSES BEFORE CORE COLLAPSE

We study the dynamical evolution of idealized stellar systems by avera ging results from many N-body simulations, each having modest numbers of stars. For isolated systems with stars of uniform mass, we discuss aspects of evolution up to the point of core collapse: relaxation and its N-dependence, the evolution of the density profile, the developmen t of the velocity dispersion and anisotropy, and the rate of stellar e scape. We find that the continuum models (gas and Fokker-Planck) agree quite accurately with N-body simulations in which N is of order of a few hundred. Small deviations from these models are present at small r adii and at radii from the half-mass radius outwards. They are probabl y associated with binary activity and with the development of anisotro py, respectively. As expected, the N-body systems are strongly anisotr opic in the outer half of the mass, while in the core the velocity dis tribution is isotropic to good approximation. Anisotropy has a very im portant influence on the rate of escape of stars. We also estimate qui te reliable values for the coefficient gamma in the Coulomb logarithm ln(gammaN) and the conductivity coefficient C in the gas model of Lynd en-Bell & Eggleton. These are gamma congruent-to 0.11 and C = 0.104, r espectively.