From the 1 of 6 linked papers with an AI index.
6 papers
Two shadows of a single black hole: Vacuum birefringence phenomena within Einstein-nonlinear-electrodynamics
Marco A. A. de Paula, Haroldo C. D. Lima, Pedro V. P. Cunha +2
The paper investigates photon propagation in black holes sourced by a nonlinear electrodynamics model, showing that vacuum birefringence leads to two distinct photon trajectories a…
Light rings on stationary axisymmetric spacetimes: blind to the topology and able to coexist
Pedro V. P. Cunha, Carlos A. R. Herdeiro, João P. A. Novo
It has been established that Black Hole (BH) spacetimes obeying some general set of assumptions always possess, at least, one light ring (per rotation sense) [arXiv:2003.06445]. Th…
Good tachyons, bad bradyons: role reversal in Einstein-nonlinear-electrodynamics models
Marco A. A. de Paula, Haroldo C. D. Lima Junior, Pedro V. P. Cunha +2
In relativistic mechanics, the 4-velocity and the 4-momentum need not be parallel. This allows their norm to have a different sign. This possibility occurs in nonlinear electrodyna…
Backreaction of perturbations around a stable Light Ring
Pedro V. P. Cunha
Light rings (LRs) - closed circular orbits of null geodesics - are key features of both black holes and horizonless ultracompact objects. While unstable LRs are relevant for the ob…
Breaking the north-south symmetry: dyonic spinning black holes with synchronized gauged scalar hair
Pedro V. P. Cunha, Carlos A. R. Herdeiro, Eugen Radu +1
We study stationary clouds of a gauged, complex scalar field on a magnetically (and possibly electrically as well) charged Kerr-Newman black hole (BH). The existence of a magnetic…
Hypershadows of higher dimensional black objects: a case study of cohomogeneity-one d=5 Myers-Perry
João P. A. Novo, Pedro V. P. Cunha, Carlos A. R. Herdeiro
What does a black hole look like? In 1+3 spacetime dimensions, the optical appearance of a black hole is a bidimensional region in the observer's sky often called the black hole sh…