Shadows and strong gravitational lensing: a brief review

By P. Cunha, Carlos A. R. Herdeiro. General Relativity and Gravitation, 2018

549 citations recorded by the source corpus.

For ultra compact objects, light rings and fundamental photon orbits (FPOs) play a pivotal role in the theoretical analysis of strong gravitational lensing effects, and of BH shadows in particular. In this short review, specific models are considered to illustrate how FPOs can be useful in order to understand some non-trivial gravitational lensing effects. This paper aims at briefly overviewing the theoretical foundations of these effects, touching also some of the related phenomenology, both in general relativity and alternative theories of gravity, hopefully providing some intuition and new insights for the underlying physics, which might be critical when testing the Kerr black hole hypothesis.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/3dcfae6c8ea9a5a1d32949ba393d379e7d828b88

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

Citations in the corpus

Spontaneous scalarisation of charged black holes: coupling dependence and dynamical features (2019, background): “y 2019, is given in [4]. Another exciting piece of observational evidence comes from the near future release of the rst image of a BH shadow by the Event Horizon Telescope collaboration [5] - see e:g:[6,7] for recent reviews on BH shadows. BHs have a surprisingly small number of macroscopic degrees ”
Black Hole Parameter Estimation from Its Shadow (2018, background): “The past decade saw more attention given to analytical investigations, observational studies, and numerical simulations of shadows (see Cunha & Herdeiro 2018).”
Testing the rotational nature of the supermassive object M87* from the circularity and size of its first image (2019, background): “In a series of seminal simulations [23], it was shown that the combination of the SMBH event horizon and gravitational lensing of nearby photons leads to the appearance of a dark shadow in combination with a bright emission ring (see also [24–26]).”
Calculating black hole shadows: Review of analytical studies (2021, methodology): “(71) Interestingly, Cunha and Herdeiro [45] have recently presented a way of calculating the shadow curve of a Kerr black hole in the form of a function β(α) by solving a cubic equation.”
Shadow cast and deflection angle of Kerr-Newman-Kasuya spacetime (2018, background): “Black hole always try to pull the surrounding matter which is known as accretion [2, 3].”
Black holes with scalar hair in light of the Event Horizon Telescope (2020, background): “an accretion disk) will appear to a distant observer as a central dark region, the so-called BH shadow, against the backdrop of a bright ring [93, 94].”
Magnetically charged black holes from non-linear electrodynamics and the Event Horizon Telescope (2019, background): “Due to the combination of a photon sphere (where photons travel along unstable circular orbits) and gravitational lensing of photons, an accreting BH surrounded by a geometrically thick, optically thin emission region will lead to the appearance of a so-called shadow, in combination with a bright em”
The imitation game: Proca stars that can mimic the Schwarzschild shadow (2021, background): “The purpose of this work is to assess this possibility in what concerns the BH shadow [49,50], for equilibrium (or near-equilibrium) BSs.”
Silhouette of M87*: A new window to peek into the world of hidden dimensions (2019, background): “Eliminating rph from α and β one obtains the contour of the shadow in the observer’s sky, dependent on the inclination angle θ0 [51].”