Statistical properties of classical gravitating particles in (2+1) dimensions

We report the statistical properties of classical particles in (2 + 1) grav ity as resulting from numerical simulations. Only particle momenta have bee n taken into account. In the range of total momentum where thermal equilibr ium is reached, the distribution function and the corresponding Boltzmann e ntropy are computed. In the presence of large gravity effects, different ex tensions of the temperature turn out to be inequivalent, the distribution f unction has a power law high-energy tail and the entropy as a function of t he internal energy presents one inflection point. When the energy approache s the open universe limit, the entropy and the mean value of the particle k inetic energy seem to diverge. (C) 2001 Elsevier Science B.V. All rights re served.