Violent relaxation of ellipsoidal clouds
  An isolated, initially cold and ellipsoidal cloud of self-gravitating
particles represents a relatively simple system to study the effects of the
deviations from spherical symmetry in the mechanism of violent relaxation.
Initial deviations from spherical symmetry are shown to play a dynamical role
that is equivalent to that of density fluctuations in the case of an initially
spherical cloud. Indeed, these deviations control the amount of particles
energy change and thus determine the properties of the final energy
distribution, particularly the appearance of two species of particles: bound
and free. Ejection of mass and energy from the system together with the
formation of a density profile decaying as $\rho(r) \sim r^{-4}$ and a
Keplerian radial velocity dispersion profile, are the prominent features
similar to those observed after the violent relaxation of spherical clouds. In
addition, we find that ejected particles are characterized by highly
non-spherical shapes, whose features can be traced in the initial deviations
from spherical symmetry that are amplified during the dynamical evolution:
particles can indeed form anisotropic configurations, like bars and/or disks,
even though the initial cloud was very close to spherical.
