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We present the theory of weak gravitational lensing in cosmologies with generalized gravity, described in the Lagrangian by a generic function depending on the Ricci scalar and a non-minimally coupled scalar field. We work out the…

Astrophysics · Physics 2009-11-10 Viviana Acquaviva , Carlo Baccigalupi , Francesca Perrotta

Observational evidence implying the accelerated expansion of the universe has been the motivation to develop various classes of modified gravity theories. One of them uses the so-called "screening mechanism", which is successful in…

General Relativity and Quantum Cosmology · Physics 2019-11-18 Noshad Khosravi Largani , Mohammad Taghi Mirtorabi

We study gravitational lensing and the bending of light in low energy scale (M_S) gravity theories with extra space-time dimensions n. We find that due to the presence of spin-2 Kaluza-Klein states from compactification, a correction to the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Xiao-Gang He , Girish C. Joshi , Bruce H. J. McKellar

By considering linear-order departures from general relativity, we compute a novel expression for the weak lensing convergence power spectrum under alternative theories of gravity. This comprises an integral over a 'kernel' of general…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-22 C. Danielle Leonard , Tessa Baker , Pedro G. Ferreira

We propose a new framework for testing gravity using cluster observations, which aims to provide an unbiased constraint on modified gravity models from Sunyaev Zel'dovich (SZ) and X-ray cluster counts and the cluster gas fraction, among…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-10 Myles A. Mitchell , Jian-hua He , Christian Arnold , Baojiu Li

Gravitational lensing is most often used as a tool to investigate the distribution of (dark) matter in the universe, but, if the mass distribution is known a priori, it becomes, at least in principle, a powerful probe of gravity itself.…

Astrophysics · Physics 2009-11-06 Daniel J. Mortlock , Edwin L. Turner

We study lensing by voids in Cubic Galileon and Nonlocal gravity cosmologies, which are examples of theories of gravity that modify the lensing potential. We find voids in the dark matter and halo density fields of N-body simulations and…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-15 Alexandre Barreira , Marius Cautun , Baojiu Li , Carlton Baugh , Silvia Pascoli

The most simple observed cases of gravitational lensing of distant quasars and galaxies by galaxies and clusters of galaxies are used to test Einstein's theory of General Relativity and Newtonian Gravity over galactic and intergalactic…

Astrophysics · Physics 2009-09-25 Arnon Dar

Despite consistent progress in numerical simulations, the observable properties of galaxy clusters are difficult to predict ab initio. It is therefore important to compare both theoretical and observational results to a direct measure of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Henk Hoekstra , Matthias Bartelmann , Haakon Dahle , Holger Israel , Marceau Limousin , Massimo Meneghetti

The almost simultaneous detection of gravitational waves and a short gamma-ray burst from a neutron star merger has put a tight constraint on the difference between the speed of gravity and light. In the four-dimensional scalar-tensor…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-17 Marco Crisostomi , Kazuya Koyama

We study the impact of neglecting lensing magnification in galaxy clustering analyses for future galaxy surveys, considering the LambdaCDM model and two extensions: massive neutrinos and modifications of General Relativity. Our study…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-25 Eleonora Villa , Enea Di Dio , Francesca Lepori

If the presence of a gravitational field breaks the Lorentz symmetry valid for special relativity, an "absolute motion" might be detectable. We summarize a scalar theory of gravity with a such "ether", which starts from a tentative…

General Physics · Physics 2011-12-09 Mayeul Arminjon

The mystery of dark energy suggests that there is new gravitational physics on long length scales. Yet light degrees of freedom in gravity are strictly limited by Solar System observations. We can resolve this apparent contradiction by…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Mark Wyman

The Beyond Horndeski class of alternative gravity theories allow for Self-accelerating de-Sitter cosmologies with no need for a cosmological constant. This makes them viable alternatives to $\Lambda$CDM and so testing their small-scale…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-08 Jeremy Sakstein , Harry Wilcox , David Bacon , Kazuya Koyama , Robert C. Nichol

We review recent progress in the construction of modified gravity models as alternatives to dark energy as well as the development of cosmological tests of gravity. Einstein's theory of General Relativity (GR) has been tested accurately…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-24 Kazuya Koyama

Model-independent parametrisations for examining departures from General Relativity have been increasingly studied over the past few years. Various observables have been used to constrain the parameters and forecasts for future surveys have…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-30 Daniel B. Thomas , Carlo R. Contaldi

In this paper we have investigated the gravitational lensing in a spherically symmetric spacetime with torsion in the generalized Einstein-Cartan-Kibble-Sciama (ECKS) theory of gravity by considering higher order terms. The torsion…

General Relativity and Quantum Cosmology · Physics 2018-06-07 Lu Zhang , Songbai Chen , Jiliang Jing

The amplification of a light beam due to intervening gravitational waves is studied. The previous Jordan frame result according to which the amplification is many orders of magnitude larger in scalar-tensor gravity than in general…

Astrophysics · Physics 2014-10-13 Valerio Faraoni , Edgard Gunzig

In this paper, we analyze the clustering of galaxies using a modified theory of gravity, in which the field content of general relativity has been be increased. This increasing in the field content of general relativity changes the large…

General Relativity and Quantum Cosmology · Physics 2019-11-06 Mir Hameeda , Behnam Pourhassan , Mir Faizal , C. P. Masroor , Rizwan Ul Haq Ansari , P. K. Suresh

We generalize the scale invariant gravity by allowing a negative kinetic energy term for the classical scalar field. This gives birth to a new scalar-tensor theory of gravity, in which the scalar field is in fact an auxiliary field. For a…

High Energy Physics - Theory · Physics 2007-05-23 Shih-Yuin Lin , Kin-Wang Ng
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