Fundamental photon orbits: Black hole shadows and spacetime instabilities
By P. Cunha, Carlos A. R. Herdeiro, Eugen Radu. 2017
140 citations recorded by the source corpus.
The standard black holes (BHs) in general relativity, as well as other ultracompact objects (with or without an event horizon) admit planar circular photon orbits. These light rings (LRs) determine several spacetime properties. For instance, stable LRs trigger instabilities and, in spherical symmetry, (unstable) LRs completely determine BH shadows. In generic stationary, axisymmetric spacetimes, nonplanar bound photon orbits may also exist, regardless of the integrability properties of the photon motion. We suggest a classification of these fundamental photon orbits (FPOs) and, using Poincare maps, determine a criterion for their stability. For the Kerr BH, all FPOs are unstable (similar to its LRs) and completely determine the Kerr shadow. But in non-Kerr spacetimes, stable FPOs may also exist, even when all LRs are unstable, triggering new instabilities. We illustrate this for the case of Kerr BHs with Proca hair, wherein, moreover, qualitatively novel shadows with a cuspy edge exist, a feature that can be understood from the interplay between stable and unstable FPOs. FPOs are the natural generalization of LRs beyond spherical symmetry and should generalize the LRs key role in different spacetime properties.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/e6566ed47580f3e037a074cd493b9539ec8ae425
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Astronomy and Astrophysics
- P. Cunha
- Carlos A. R. Herdeiro
- Eugen Radu
- N. Sanchis-Gual
- Alexandre M. Pombo
- Jiliang Jing
- Songbai Chen
- Mingzhi Wang
In Nuclear and High Energy Physics
- P. Cunha
- Carlos A. R. Herdeiro
- Eugen Radu
- N. Sanchis-Gual
- Alexandre M. Pombo
- Jiliang Jing
- Songbai Chen
- V. Cardoso
Citations in the corpus
- The imitation game: Proca stars that can mimic the Schwarzschild shadow (2021, background): “The existence of LRs around BHs impacts on important strong gravity features, such as (the initial part of) the ringdown [54] and the BH shadow [55].”
- Shadow casted by a Konoplya-Zhidenko rotating non-Kerr black hole (2017, background): “The further analysis show that these novel patterns in shadows are related to the non-planar bound photon orbits, which are also called as the fundamental photon orbits (FPOs) [32].”
- Shadows and strong gravitational lensing: a brief review (2018, methodology): “Nevertheless, for generic stationary and axisymmetric spacetimes, one can define FPOs as follows [32]:”