scholarly journals Gravitational Lensing in Presence of Plasma: Strong Lens Systems, Black Hole Lensing and Shadow

Universe ◽  
2017 ◽  
Vol 3 (3) ◽  
pp. 57 ◽  
Author(s):  
Gennady Bisnovatyi-Kogan ◽  
Oleg Tsupko
Keyword(s):  
Black Hole ◽  
Gravitational Lensing

scholarly journals Null Geodesics and Strong Field Gravitational Lensing in a String Cloud Background

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
M. Sharif ◽  
Sehrish Iftikhar
Keyword(s):  
Black Hole ◽  
Gravitational Lensing ◽  
Galactic Center ◽  
Deflection Angle ◽  
Orbital Motion ◽  
Strong Field ◽  
Schwarzschild Black Hole ◽  
Field Limit ◽  
Null Geodesics ◽  
Supermassive Black Hole

This paper is devoted to studying two interesting issues of a black hole with string cloud background. Firstly, we investigate null geodesics and find unstable orbital motion of particles. Secondly, we calculate deflection angle in strong field limit. We then find positions, magnifications, and observables of relativistic images for supermassive black hole at the galactic center. We conclude that string parameter highly affects the lensing process and results turn out to be quite different from the Schwarzschild black hole.

scholarly journals Weak Deflection Angle of some Classes of non-linear Electrodynamics Black Holes via Gauss-Bonnet Theorem

2020 ◽  
Author(s):  
Hasan El Moumni ◽  
Karima Masmar ◽  
Ali Övgün
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Lensing ◽  
Deflection Angle ◽  
Weak Field ◽  
Leading Order ◽  
Plasma Medium ◽  
Non Linear ◽  
The Deflection Angle ◽  
Bonnet Theorem

In this paper, we study the gravitational lensing by some black hole classes within the non-linear electrodynamics in weak field limits. First, we calculate an optical geometry of the non-linear electrodynamics black hole then we use the Gauss-Bonnet theorem for finding deflection angle in weak field limits. The effect of non-linear electrodynamics on the deflection angle in leading order terms is studied. Furthermore, we discuss the effects of the plasma medium on the weak deflection angle.

Back Where We Started

2017 ◽  
Author(s):  
John A. Adam
Keyword(s):  
Integral Equation ◽  
Black Hole ◽  
Angular Momentum ◽  
Gravitational Lensing ◽  
Airy Functions ◽  
Ray Optics ◽  
Gravitational Fields ◽  
The Subject ◽  
Luneberg Lens

This chapter returns to the subject of rainbows, offering some reflections based on the author's review of the book The Rainbow Bridge: Rainbows in Art, Myth, and Science by Raymond L. Lee, Jr. and Alistair B. Frase. In particular, it discusses various topics related to the rainbow, including historical descriptions of the rainbow, some common misperceptions about rainbows, theories of the rainbow, angular momentum, rainbow ray, and Airy functions. The chapter also considers ray optics, with emphasis on Luneberg inversion and gravitational lensing, Abel's integral equation, and the Luneberg lens. Finally, it explains the rainbow's connection with classical scattering and gravitational lensing, focusing on weak gravitational fields and the black hole lens.

scholarly journals Deflection of light and shadow cast by a dual-charged stringy black hole

2020 ◽  
Vol 35 (28) ◽  
pp. 2050177
Author(s):  
Shubham Kala ◽  
Saurabh ◽  
Hemwati Nandan ◽  
Prateek Sharma
Keyword(s):  
Black Hole ◽  
Gravitational Lensing ◽  
Compact Object ◽  
Physical Nature ◽  
Space Time ◽  
Deflection Of Light ◽  
Shadow Cast ◽  
Light And Shadow ◽  
The Impact ◽  
The Universe

Gravitational lensing and black hole shadows are one of the strongest observational evidences to prove the existence of black holes in the universe. The gravitational lensing arises due to the deflection of light by the gravitational field of a gravitating body such as a black hole. Investigation of the shadow cast by a compact object as well as deflection of light around it may provide the useful information about physical nature of the particular compact object and other related aspects. In this paper, we study the deflection of light by a dual-charged stringy black hole space–time derived in dilaton-Maxwell gravity. The variation of deflection angle with the impact parameter for different values of electric and magnetic charges is studied. We also study the shadow of this black hole space–time to obtain the radius of shadow cast by it. We have considered an optically thin emission disk around it and observed that there are not significant changes in the shadow cast by this black hole compared to well-known Schwarzschild black hole space–time in GR.

scholarly journals Weak and strong deflection gravitational lensing by a renormalization group improved Schwarzschild black hole

2019 ◽  
Vol 79 (12) ◽  
Author(s):  
Xu Lu ◽  
Yi Xie
Keyword(s):  
Black Hole ◽  
Renormalization Group ◽  
Gravitational Lensing ◽  
Galactic Center ◽  
Quantum Effect ◽  
Apparent Size ◽  
Great Care ◽  
Schwarzschild Black Hole ◽  
Sgr A ◽  
Near Future

AbstractWeak and strong deflection gravitational lensing by a renormalization group improved Schwarzschild black hole is investigated and its observables are found. By taking the supermassive black holes Sgr A* and M87* respectively in the Galactic Center and at the center of M87 as lenses, we estimate these observables and analyse possibility of detecting this quantum improvement. It is not feasible to distinguish such a black hole by most observables in the near future except for the apparent size of the shadow. We also note that directly using measured shadow of M87* to constrain this quantum effect requires great care.

scholarly journals Gravitational lensing of a star by a rotating black hole

JETP Letters ◽  
2017 ◽  
Vol 106 (10) ◽  
pp. 637-642 ◽  
Author(s):  
V. I. Dokuchaev ◽  
N. O. Nazarova
Keyword(s):  
Black Hole ◽  
Gravitational Lensing ◽  
Rotating Black Hole
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