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    Relativistic thick discs in the Kerr de Sitter backgrounds

    Zdeněk Stuchlík · Září 01, 2005 · Fyzika · 0 comments
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    Publication date: Sep 2005

    Abstract:
    Perfect fluid tori with a uniform distribution of the specific angular
    momentum, ell(r, θ) = const, orbiting the Kerr de Sitter black holes or
    naked singularities are studied. It is well known that the structure of
    equipotential surfaces of such marginally stable tori reflects the basic
    properties of any tori with a general distribution of the specific
    angular momentum. Closed equipotential surfaces corresponding to
    stationary thick discs are allowed only in the spacetimes admitting
    stable circular geodesics. The last closed surface crosses itself in the
    cusp(s) enabling the outflow of matter from the torus due to the
    violation of hydrostatic equilibrium. The inner cusp enables an
    accretion onto the central object. The influence of the repulsive
    cosmological constant, Λ > 0, on the equipotential surfaces lies in
    the existence of the outer cusp (with a stabilizing effect on the thick
    discs) and in the strong collimation of open equipotential surfaces
    along the rotational axis. Both the effects take place near a so-called
    static radius where the gravitational attraction is just balanced by the
    cosmic repulsion. The outer cusp enables excretion, i.e., the outflow of
    matter from the torus into the outer space. The plus-family discs (which
    are always co-rotating in the black-hole backgrounds but can be counter-
    rotating, even with negative energy of the fluid elements, in some
    naked-singularity backgrounds) are thicker and more extended than the
    minus-family ones (which are always counter-rotating in all
    backgrounds). For co-rotating discs in the naked-singularity spacetimes,
    the potential well between the centre of the disc and its edges at the
    cusps is usually much higher than in the black-hole spacetimes. If the
    parameters of naked-singularity spacetimes are very close to the
    parameters of extreme black-hole spacetimes, the family of possible
    disc-like configurations includes members with two isolated discs where
    the inner one is always a counter-rotating accretion disc.

    Authors:
    Slaný, Petr; Stuchlík, Zdenek;

    https://ui.adsabs.harvard.edu/abs/2005CQGra..22.3623S

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