664 citations · 3.3k across the 54 of their papers we have counts for
54 papers
Gravitational lensing in Brill spacetimes
Mourad Halla, Volker Perlick
We consider the Brill metric which is an electrovacuum solution to Einstein's field equation. It depends on three parameters, a mass parameter , a NUT parameter and a charge…
Light propagation in a plasma on an axially symmetric and stationary spacetime: Separability of the Hamilton-Jacobi equation and shadow
Barbora Bezdekova, Volker Perlick, Jiri Bicak
The properties of light rays around compact objects surrounded by a plasma are affected by both strong gravitational fields described by a general-relativistic spacetime and by a d…
Photon sphere and shadow of a time-dependent black hole described by a Vaidya metric
Jay Solanki, Volker Perlick
In this paper we derive exact analytical formulas for the evolution of the photon sphere and for the angular radius of the shadow in a special Vaidya spacetime. The Vaidya metric d…
A Morse-theoretical analysis of lensing in wormhole spacetimes
Mourad Halla, Volker Perlick
We consider a class of stationary and axisymmetric wormhole spacetimes that is closely related to, but not identical with, the class of Teo wormholes. We fix a point (observati…
Calculating black hole shadows: Review of analytical studies
Volker Perlick, Oleg Yu. Tsupko
In this article, we provide a review of the current state of the research of the black hole shadow, focusing on analytical (as opposed to numerical and observational) studies. We s…
Geometrically thick tori around compact objects with a quadrupole moment
Jan-Menno Memmen, Volker Perlick
We study geometrically thick perfect-fluid tori with constant specific angular momentum, so-called "Polish doughnuts", orbiting deformed compact objects with a quadrupole moment. M…