Publication date: Mar 2019
Abstract:
Three well-known exact regular solutions of general relativity coupled
to nonlinear electrodynamics (NED), namely the Maxwellian, Bardeen, and
Hayward regular spacetimes, which can describe either a regular black
hole or a geometry without horizons, have been considered. Relaxation
times for the scalar, electromagnetic (EM) and gravitational
perturbations of black holes and no-horizon spacetimes have been
estimated in comparison with the ones of the Schwarzschild and Reissner-
Nordström spacetimes. It has been shown that the considered geometries
in general relativity coupled to the NED have never-vanishing circular
photon orbits, and on account of this fact, these spacetimes always
oscillate the EM perturbations with quasinormal frequencies. Moreover,
we have shown that the EM perturbations in the eikonal regime can be a
powerful tool to confirm (i) that the light rays do not follow null
geodesics in the NED by the relaxation rates and (ii) if the underlying
solution has a correct weak field limit to the Maxwell electrodynamics
by the angular velocity of the circular photon orbit.
Authors:
Toshmatov, Bobir; Stuchlík, Zdeněk; Ahmedov, Bobomurat; Malafarina, Daniele;