Violent relaxation of ellipsoidal clouds

Abstract

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.

12 pages, 19 figures

References in corpus (5)

• A Vast Thin Plane of Co-rotating Dwarf Galaxies Orbiting the Andromeda Galaxy
• Velocity anti-correlation of diametrically opposed galaxy satellites in the low redshift universe
• Violent and mild relaxation of an isolated self-gravitating uniform and spherical cloud of particles
• Universal properties of violently relaxed gravitational structures
• Spherical symmetry breaking in cold gravitational collapse of isolated systems

Cited by in corpus (2)

• Gaussian random field power spectrum and the Sérsic law
• On the generation of triaxiality in the collapse of cold spherical self-gravitating systems