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Weyl's conformal gravity theory, which is considered as a compelling alternative to general relativity theory, has been claimed to describe the observed flat rotation curve feature of spiral galaxies without the need of invoking dark…

General Relativity and Quantum Cosmology · Physics 2023-07-12 Shubhrangshu Ghosh , Mahasweta Bhattacharya , Yanzi Sherpa , Arunava Bhadra

The conformal gravity fit to observed galactic rotation curves requires {\gamma}>0. On the other hand, conventional method for light deflection by galaxies gives a negative contribution to Schwarzschild value for {\gamma}>0, which is…

General Relativity and Quantum Cosmology · Physics 2015-06-15 Carlo Cattani , Massimo Scalia , Ettore Laserra , Ivana Bochicchio , Kamal K. Nandi

The Weyl gravity appears to be a very peculiar theory. The contribution of the Weyl linear parameter to the effective geodesic potential is opposite for massive and nonmassive geodesics. However, photon geodesics do not depend on the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 S. Pireaux

Light deflection offers an unbiased test of Weyl's gravity since no assumption on the conformal factor needs to be made. In this second paper of our series ``Light deflection in Weyl gravity'', we analyze the constraints imposed by light…

General Relativity and Quantum Cosmology · Physics 2009-11-10 S. Pireaux

We calculate the deflection angle of light from a distant source by a galaxy cluster in Weyl's conformal gravity. The general method of calculation is first applied to calculate the deflection angle in Schwarzschild-de Sitter (Kottler)…

General Relativity and Quantum Cosmology · Physics 2019-10-18 Oguzhan Kasikci , Cemsinan Deliduman

We examine the viability of Weyl conformal gravity as an alternative to the general theory of relativity. By using the extended rotation curve of the Milky Way and velocity dispersions of four globular clusters, we show that Weyl gravity…

General Relativity and Quantum Cosmology · Physics 2018-12-19 Koushik Dutta , Tousif Islam

Conformal Weyl Gravity (CWG) predicts galactic rotation curves without invoking dark matter. This makes CWG an interesting candidate theory as an alternative to GR. This removal of the necessity of dark matter arises because the exact…

General Relativity and Quantum Cosmology · Physics 2014-04-01 Deandra Cutajar , Kristian Zarb Adami

We estimate the changes in solar system tests of general relativity when "dark energy" arises from a Weyl scaling invariant action, using the modified Schwarzschild-like spherically symmetric solution obtained in this case by Adler and…

General Relativity and Quantum Cosmology · Physics 2023-01-11 Stephen L. Adler

The higher dimensional Weyl curvature induces on the brane a new source of gravity. This Weyl fluid of geometrical origin (reducing in the spherically symmetric, static configuration to a dark radiation and dark pressure) modifies…

General Relativity and Quantum Cosmology · Physics 2015-06-05 K. C. Wong , T. Harko , K. S. Cheng , L. Á. Gergely

A very general class of axially-symmetric metrics in general relativity (GR) that includes rotations is used to discuss the dynamics of rotationally-supported galaxies. The exact vacuum solutions of the Einstein equations for this extended…

General Relativity and Quantum Cosmology · Physics 2023-02-15 Yogendra Srivastava , Giorgio Immirzi , John Swain , Orland Panella , Simone Pacetti

Recently, there has been an interest in inflation and modified gravity with a Weyl term added to the general-relativistic action (N. Derulle, M. Sasaki, Y. Sendouda and A. Youssef, JCAP, 3, 040 (2011)). In this paper we study empirical…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-13 Wei-Tou Ni

We investigate the possibility that the observed behavior of test particles outside galaxies, which is usually explained by assuming the existence of dark matter, is the result of the dynamical evolution of particles in a Weyl type…

General Relativity and Quantum Cosmology · Physics 2024-11-18 Piyabut Burikham , Tiberiu Harko , Kulapant Pimsamarn , Shahab Shahidi

We propose a novel test of gravity that combines galaxy clustering with gravitational lensing. In general relativity, the evolution of matter density fluctuations and of the Weyl potential -- the sum of spatial and temporal distortions of…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-06 Camille Bonvin , Nastassia Grimm , Isaac Tutusaus

We present a novel test of general relativity (GR): measuring the geometric component of the time delay due to gravitational lensing. GR predicts that photons and gravitational waves follow the same geodesic paths and thus experience the…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-19 David Rubin , Istvan Szapudi , Benjamin J. Shappee , Gagandeep S. Anand

The Weyl geometric gravity theory, in which the gravitational action is constructed from the square of the Weyl curvature scalar and the strength of the Weyl vector, has been intensively investigated recently. The theory admits a…

General Relativity and Quantum Cosmology · Physics 2025-11-19 Mohsen Khodadi , Tiberiu Harko

Among the so-called classical tests of general relativity (GR), light bending has been confirmed with an accuracy that increases as times goes by. Here we study the gravitational deflection of photons within the framework of classical and…

High Energy Physics - Theory · Physics 2015-06-11 Antonio Accioly , José Helayël-Neto , Breno Giacchini , Wallace Herdy

We discuss, without assuming asymptotic flatness, a gravitational lens for an observer and source that are within a finite distance from a lens object. The proposed lens equation is consistent with the deflection angle of light that is…

General Relativity and Quantum Cosmology · Physics 2020-09-30 Keita Takizawa , Toshiaki Ono , Hideki Asada

We study light propagation and gravitational lensing in scalar-tensor theories of gravity by using a static, axisymmetric exterior solution. The solution has asymptotic flatness properties and is reduced to Voorhees's one in the case of a…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Shin-ei Tsuneishi , Kazuya Watanabe , Tooru Tsuchida

If it is hypothesised that there is no dark matter then some alternative gravitational theory must take the place of general relativity (GR) on the largest scales. Dynamical measurements can be used to investigate the nature of such a…

Astrophysics · Physics 2008-11-26 Daniel J. Mortlock , Edwin L. Turner

When the full connection of Weyl conformal gravity is varied instead of just the metric, the resulting vacuum field equations reduce to the vacuum Einstein equation, up to the choice of local units, if and only if the torsion vanishes. This…

General Relativity and Quantum Cosmology · Physics 2014-07-30 James T. Wheeler
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