scholarly journals Gravitational lensing effect in traversable wormholes

2021 ◽  
pp. 168460
Author(s):  
Nisha Godani ◽  
Gauranga C. Samanta
Keyword(s):  
Gravitational Lensing ◽  
Traversable Wormholes ◽  
Lensing Effect

Wormholes solutions in f(R,T) gravity with photon sphere at the throat

2021 ◽  
pp. 2150211
Author(s):  
Nisha Godani
Keyword(s):  
General Relativity ◽  
Gravitational Lensing ◽  
Shape Function ◽  
Traversable Wormholes ◽  
Lensing Effect

This work is aimed at the study of traversable wormholes, proposed by Morris and Thorne [Wormholes in spacetime and their use for interstellar travel: A tool for teaching general relativity, Am. J. Phys. 56 (1988) 395], in the framework of [Formula: see text] gravity, where [Formula: see text], [Formula: see text] and [Formula: see text] are constants. The wormhole solutions are obtained and analyzed by using a simplest form of shape function. Further, the existence of photon spheres outside the throat of wormhole due to the gravitational lensing effect is detected.

Charged traversable wormholes in f(R) gravity

2021 ◽  
pp. 2150098
Author(s):  
Nisha Godani ◽  
Gauranga C. Samanta
Keyword(s):  
Gravitational Lensing ◽  
Deflection Angle ◽  
Strong Field ◽  
Energy Condition ◽  
Weak Energy Condition ◽  
Exotic Matter ◽  
Field Limit ◽  
Traversable Wormholes ◽  
The Deflection Angle ◽  
Lensing Effect

This work is focused on the study of charged wormholes in the following two aspects: (i) to obtain exotic matter free effective charged wormhole solutions and (ii) to determine deflection angle for gravitational lensing effect. We have defined a novel redshift function, obtained wormhole solutions using the background of [Formula: see text] theory of gravity and found the regions obeying the weak energy condition. Further, the gravitational lensing effect is analyzed by determining the deflection angle in terms of strong field limit coefficients.

scholarly journals Traversable wormholes in Einsteinian cubic gravity

2019 ◽  
Vol 35 (06) ◽  
pp. 2050017 ◽  
Author(s):  
Mohammad Reza Mehdizadeh ◽  
Amir Hadi Ziaie
Keyword(s):  
Equation Of State ◽  
Gravitational Lensing ◽  
Energy Condition ◽  
Higher Order ◽  
Energy Conditions ◽  
Geodesic Motion ◽  
De Sitter ◽  
Asymptotically Flat ◽  
Traversable Wormholes ◽  
Standard Energy

In this work, we investigate wormhole configurations described by a constant redshift function in Einstein-Cubic gravity ( ECG ). We derive analytical wormhole geometries by assuming a particular equation of state ( EoS ) and investigate the possibility that these solutions satisfy the standard energy conditions. We introduce exact asymptotically flat and anti-de Sitter (AdS) spacetimes that admit traversable wormholes. These solutions are obtained by imposing suitable values for the parameters of the theory so that the resulted geometries satisfy the weak energy condition ( WEC ) in the vicinity of the throat, due to the presence of higher-order curvature terms. Moreover, we find that AdS solutions satisfy the WEC throughout the spacetime. A description of the geodesic motion of time-like and null particles is presented for the obtained wormhole solutions. Also, using gravitational lensing effects, observational features of the wormhole structure are discussed.

scholarly journals Is the Giant Luminous Arc in A370 a Gravitational Lensing Effect?

1988 ◽  
Vol 130 ◽  
pp. 463-465
Author(s):  
Y. Mellier
Keyword(s):  
Gravitational Lensing ◽  
Distant Cluster ◽  
Cluster Of Galaxies ◽  
Lensing Effect

A gravitational lensing model is proposed to explain the giant arc structure we observed in September 1985 in the distant cluster of galaxies Abell 370 (z=0.37.4).

scholarly journals Luminosity Inhomogeneity of Quasars and the Upper Limit of the Density Fluctuation in the Universe

1990 ◽  
Vol 139 ◽  
pp. 418-419
Author(s):  
Yaoquan Chu ◽  
Lizhi Fang
Keyword(s):  
Gravitational Lensing ◽  
Density Fluctuation ◽  
Density Inhomogeneity ◽  
Upper Limit ◽  
Lensing Effect ◽  
The Universe

An upper limit to the amplitude of the overall density fluctuation has been found by means of the gravitational lensing effect of the density inhomogeneity on luminosity of quasars with large redshifts. The observed differences of luminosities of quasars located at different directions are partially given by the lensing effect; therefore, a useful upper limit to the inhomogeneity can be derived.

scholarly journals GRAVITATIONAL LENSING AND CATASTROPHE THEORY

1995 ◽  
Vol 04 (06) ◽  
pp. 685-710 ◽  
Author(s):  
YUUKO KAKIGI ◽  
TAKASHI OKAMURA ◽  
TAKESHI FUKUYAMA
Keyword(s):  
Gravitational Lensing ◽  
Catastrophe Theory ◽  
Multipole Expansion ◽  
Numerical Calculations ◽  
Lensing Effect ◽  
Expansion Model

Singularities of caustics appearing in the gravitational lensing effect are discussed analytically. The multipole expansion model of the lensing object is mainly studied since it is tractable and universal. Our analyses are confirmed by numerical calculations and applied to the multiple quasar system of PG1115+080. Consistencies with elliptical lens models are also discussed.

Sign in / Sign up

Export Citation Format

Share Document