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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

The effects of several dark energy models on gravitational time delay of particles with non-zero mass are investigated and analytical expressions for the same are obtained at the first order accuracy. Also the expression for gravitational…

General Relativity and Quantum Cosmology · Physics 2016-08-24 Tamal Sarkar , Shubhrangshu Ghosh , Arunava Bhadra

It has recently been suggested that observed galaxy rotation curves can be accounted for by general relativity without recourse to dark-matter halos. Good fits have been produced to observed galatic rotation curves using this model. We show…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Dylan Menzies , Grant J. Mathews

We focus on a modified version of Horava - Lifschitz theory and, in particular, we consider the impact of its weak - field static spherically symmetric limit on the galaxy dynamics. In a previous paper, we used the modified gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Vincenzo F. Cardone , Monica Capone , Ninfa Radicella , Matteo L. Ruggiero

We show quantitatively that an exact solution of Einstein's conformal gravity can explain very well the galactic rotation curves for a sample of 104 galaxies without need for dark matter or other exotic modification of gravity. The metric…

General Relativity and Quantum Cosmology · Physics 2019-06-13 Qiang Li , Leonardo Modesto

In this work, we submit the explanation of spectra of the rotary curves of galaxies on the basis of a vector theory of gravitation without regard to the dark matter hypothesis. We study the approximation of rotary curves in case of existing…

General Physics · Physics 2011-05-10 V. N. Borodikhin

After explaining the motivation for this article, I briefly recapitulate the methods used to determine, somewhat coarsely, the rotation curves of our Milky Way Galaxy and other spiral galaxies, especially in their outer parts, and the…

Astrophysics · Physics 2008-04-25 Dilip G. Banhatti

The flatness of galaxy rotation curves at large radii is generally considered to be a significant piece of evidence in support of the existence of dark matter. Several studies have claimed that post-Newtonian corrections to the Newtonian…

Astrophysics of Galaxies · Physics 2023-07-05 Kostas Glampedakis , David Ian Jones

We present a detailed investigation of the properties of the galactic rotation curves in the Weyl geometric gravity model, in which the gravitational action is constructed from the square of the Weyl curvature scalar, and of the strength of…

General Relativity and Quantum Cosmology · Physics 2023-11-29 Maria Crăciun , Tiberiu Harko

In this work the phenomenology of models possessing a non-minimal coupling between matter and geometry is discussed, with a particular focus on the possibility of describing the flattening of the galactic rotation curves as a dynamically…

Astrophysics of Galaxies · Physics 2015-05-18 Orfeu Bertolami , Jorge Páramos

Many cosmological observations call for the existence of dark matter. The most direct evidence for dark matter is inferred from the measured flatness of galactic rotation curves. The latter is based on Newtonian gravity. Alternative…

General Relativity and Quantum Cosmology · Physics 2008-11-19 Aleksandar Rakic , Dominik J. Schwarz

The missing of a Keplerian fall-off in the observed galaxy rotation curves represents classical evidence for the existence of dark matter on galactic scales. There has been some recent activity concerning the potential of modelling galactic…

General Relativity and Quantum Cosmology · Physics 2010-02-17 Aleksandar Rakic , Dominik J. Schwarz

Conformal gravity theory can explain observed flat rotation curves of galaxies without invoking hypothetical dark matter. Within this theory, we obtain a generic formula for the sizes of galaxies exploiting the stability criterion of…

General Relativity and Quantum Cosmology · Physics 2012-08-28 Kamal K. Nandi , Arunava Bhadra

In this thesis, we investigate some aspects of dark matter phenomenology and its predictive power in explaining the flattening of galaxy rotation curves at large distances. After outlining the Standard Model of particle physics, its…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-31 Kirill Zatrimaylov

The dark matter accretion theory (around a central body) of the author on the basis of his 5-dimensional Projective Unified Field Theory (PUFT) is applied to the orbital motion of stars around the center of the Galaxy. The departure of the…

General Relativity and Quantum Cosmology · Physics 2009-11-07 E. Schmutzer

The rotation curves of low surface brightness galaxies provide a unique data set with which to test alternative theories of gravitation over a large dynamic range in size, mass, surface density, and acceleration. Many clearly fail,…

Astrophysics · Physics 2015-06-24 Stacy McGaugh , Erwin de Blok

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

Flat rotation curves in disk galaxies represent the main evidence for large amounts of surrounding dark matter. Despite of the difficulty in identifying the dark matter contribution to the total mass density in our Galaxy, stellar…

Astrophysics of Galaxies · Physics 2020-06-15 Mariateresa Crosta , Marco Giammaria , Mario G. Lattanzi , Eloisa Poggio

Motivated by an axiomatic approach to characterize space-time it is investigated a reformulation of Einstein's gravity where the pseudo-riemannian geometry is substituted by a Weyl one. It is presented the main properties of the Weyl…

General Relativity and Quantum Cosmology · Physics 2011-12-19 F. P. Poulis , J. M. Salim

We study the weak-field limit of the conformal Weyl gravity suggested by Mannheim as an alternative to Einstein's General Relativity modeling both dark matter and dark energy. We solve the field equations of the theory in the weak-field…

Astrophysics · Physics 2014-11-18 O. V. Barabash , H. P. Pyatkovska