Routing (electronic design automation)

Quantum mechanics

de Sitter–Schwarzschild metric

Mathematical physics

Covariant transformation

Rotating black hole

Telecommunications

Geodesic

Computer science

Classical mechanics

Computer network

Routing protocol

Physics

Penrose process

Mathematics

Optics

Light cone

Angular momentum

Link-state routing protocol

Isotropy

Reference frame

Geometry

Black hole (networking)

Frame (networking)

The European Physical Journal C

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.

Light escape cones in local reference frames of Kerr–de Sitter black hole spacetimes and related black hole shadows