Results 101 to 110 of about 84,325 (117)

Weak gravitational lensing

, 2013
Lecture given as part of the International School of Physics Enrico Fermi "New Horizons for Observational Cosmology", Varenna, July 1-6, 2013, eds. A. Melchiori, A. Cooray, E.
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Weak Gravitational Lensing

, 2020
In this presentation I review cosmological measurements with weak gravitational lensing using the cosmic shear technique. An intriguing tension in the parameter S8=sigma8*sqrt(Omega_m/0.3) between low-z large-scale-structure probes and the Planck primary CMB probes has been observed. This is reminiscent of the well-known H0 tension, albeit currently at
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Gravitational lensing phenomena of Ellis-Bronnikov-Morris-Thorne wormhole with global monopole and cosmic string

Physics Letters B
In this paper, we theoretically investigate gravitational lensing within the space-time framework of traversable wormholes, focusing on the combined effects of a global monopole and a cosmic string.
Faizuddin Ahmed, İzzet Sakallı, Ahmad Al-Badawi   +2 more
doaj  

Forecasting the Detection of Lyman-alpha Forest Weak Lensing from the Dark Energy Spectroscopic Instrument and Other Future Surveys

The Open Journal of Astrophysics
The apparent angular positions of quasars are deflected on the sky by the gravitational field sourced by foreground matter. This weak lensing effect is measurable through the distortions it introduces in the lensed quasar spectra.
Patrick Shaw, Rupert A. C. Croft, R. Benton Metcalf   +2 more
doaj   +1 more source

A novel gravitational lensing feature by wormholes

Physics Letters B, 2019
Horizonless compact objects with light rings (or photon spheres) are becoming increasingly popular in recent years for several reasons. In this paper, we show that a horizonless object such as a wormhole of Morris–Thorne type can have two photon spheres.
Rajibul Shaikh, Pritam Banerjee, Suvankar Paul, Tapobrata Sarkar   +3 more
doaj  

Gravitational Lensing in gamma-ray bursts [PDF]

arXiv
Gravitationally lensed Gamma-ray bursts (GRBs) offer critical advantages over other lensed sources. They can be detected via continuously operating detectors covering most of the sky. They offer extremely high time resolution to determine lensing delays and find short-time delays accurately.
arxiv  

Light bending and gravitational lensing in Brans-Dicke theory

Physics Letters B, 2019
As an important candidate theory of gravity, Brans-Dicke theory has been widely studied. In this paper, we investigate light bending and gravitational lensing by compact objects in Brans-Dicke theory in weak gravitational field.
Xiaojun Gao, Shupeng Song, Jinsong Yang
doaj  

Shadows and photon spheres in static and rotating traversable wormholes

Nuclear Physics B
We explore the shadows and photon orbits of both static and rotating traversable wormholes by employing a redshift function in combination with two distinct shape functions.
Takol Tangphati, Phongpichit Channuie, Kazuharu Bamba, Davood Momeni   +3 more
doaj  

Quasars and Gravitational Lenses [PDF]

Science, 1984
Despite the expenditure of large amounts of telescope time and other resources, most of the fundamental questions concerning quasi-stellar objects (quasars) remain unanswered. A complex phenomenology of radio, infrared, optical, and x-ray properties has accumulated but has not yielded even a satisfactory classification system.
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Galaxies as Gravitational Lenses [PDF]

Science, 1967
The probability that a galaxy gathers light from another remote galaxy, and deflects and focuses it toward an observer on Earth, is calculated according to various cosmologic models. I pose the question of whether an object called a quasar is a single, intrinsically luminous entity or the result of accidental alignment, along the line of sight, of two ...
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