2018/03/01 by Zdeněk Stuchlík, Daniel Charbulák, Jan Schee · 106 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Black hole (networking) #Covariant transformation #Geodesic #Light cone #Penrose process #Photon #Position (finance) #Pulsars and Gravitational Waves Research #Reference frame #Relativity and Gravitational Theory #gr-qc
paper · pdf · doi:10.1140/epjc/s10052-018-5578-6
published in The European Physical Journal C 78(3) (Springer Science+Business Media) · 58 pages, 136 figures
openalex publication_date 2018/03/01 · openalex created_date 2018/03/29 · arxiv created 2018/10/31 · arxiv updated 2018/11/02 · openalex updated_date 2026/08/05
We construct the light escape cones of isotropic spot sources of radiation residing in special classes of reference frames in the Kerr–de Sitter (KdS) black hole spacetimes, namely in the fundamental class of ‘non-geodesic’ locally non-rotating reference frames (LNRFs), and two classes of ‘geodesic’ frames, the radial geodesic frames (RGFs), both falling and escaping, and the frames related to the circular geodesic orbits (CGFs). We compare the cones constructed in a given position for the LNRFs, RGFs, and CGFs. We have shown that the photons locally counter-rotating relative to LNRFs with positive impact parameter and negative covariant energy are confined to the ergosphere region. Finally, we demonstrate that the light escaping cones govern the shadows of black holes located in front of a radiating screen, as seen by the observers in the considered frames. For shadows related to distant static observers the LNRFs are relevant.