Publication date: Apr 2016
Abstract:
Shape and frequency-shift maps of direct and indirect images of
Keplerian discs orbiting in Bardeen and
Ayòn-Beato-Garcìa (ABG) black hole and no-horizon
spacetimes are determined. Then profiles of spectral lines generated in
the innermost parts of the Keplerian discs in the Bardeen and ABG
spacetimes are constructed. The frequency-shift maps and profiled
spectral lines are compared to those generated in the field of
Schwarzschild black holes and possible observationally relevant
signatures of the regular black hole and no-horizon spacetimes are
discussed. We demonstrate that differences relative to the Schwarzschild
spacetimes are for the no-horizon spacetimes much more profound in
comparison to the regular black hole spacetimes and increase with
increasing charge parameter of the spacetime. The differences are
greater for small and large inclination angles than for intermediate
ones. For the no-horizon spacetimes, the differences enable us to
distinguish the Bardeen and ABG spacetime, if inclination angle to the
distant observer is known. We also show that contribution of the
so-called ghost images to the profiled lines increases with increasing
charge parameter of the spacetimes.
Authors:
Schee, Jan; Stuchlík, Zdeněk;