Publication date: Jan 2017
Abstract:
A new intrinsically-relativistic kinetic mechanism for generation of
nonisotropic relativistic kinetic equilibria in collisionless N-body
systems is pointed out. The theory is developed in the framework of the
covariant Vlasov statistical description. The new effect is based on the
constraints placed by the conservation laws of neutral single-particle
dynamics in prescribed background curved-spacetimes demonstrating
existence of Killing tensors. As an illustration, the particular case of
the Kerr spacetime admitting the so-called Carter constant for the
particle geodesic motion is considered. The general functional form of
the equilibrium kinetic distribution function (KDF) is determined and an
explicit realization in terms of Gaussian-like distributions is
provided. It is shown that, due to the Carter constant, these
equilibrium KDFs exhibit an anisotropic phase-space functional
dependence in terms of the single-particle 4-velocity components, giving
rise to corresponding nonisotropic continuum fluid fields. The
qualitative properties of the equilibrium stress-energy tensor
associated with these systems are discussed, with a particular emphasis
on the related occurrence of temperature anisotropy effects. The theory
is susceptible of astrophysical applications, including in particular
the statistical properties of dark matter (DM) halos around stellar-mass
or galactic-center black holes.
Authors:
Cremaschini, Claudio; Stuchlík, Zdeněk;