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Related papers: Constraining MOdified Gravity with the S2 Star

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We provide a cosmological test of modified gravity with two tensorial degrees of freedom and no extra propagating scalar mode. The theory of gravity we consider admits a cosmological model that is indistinguishable from the $\Lambda$CDM…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-01 Takashi Hiramatsu , Tsutomu Kobayashi

The cosmic curvature density parameter has been constrained in the present work independent of any background cosmological model. The reconstruction is performed adopting the non-parametric Gaussian Processes (GP). The constraints on…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-18 Purba Mukherjee , Narayan Banerjee

In 'modified' gravity the observed acceleration of the universe is explained by changing the gravitational force law or the number of degrees of freedom in the gravitational sector. Both possibilities can be tested by measurements of…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-27 Clare Burrage , David Parkinson , David Seery

We revisit the cosmological viability of the Hu $\&$ Sawicki modified gravity scenario. The impact of such a modification on the different cosmological observables, including gravitational waves, is carefully described. The most recent…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-19 Lotfi Boubekeur , Elena Giusarma , Olga Mena , Hector Ramirez

Eddington-inspired Born-Infeld gravity is an important modification of Einstein's general relativity, which can give rise to non-singular cosmologies at the classical level, and avoid the end-stage singularity in a gravitational collapse…

General Relativity and Quantum Cosmology · Physics 2022-01-12 Pritam Banerjee , Debojyoti Garain , Suvankar Paul , Rajibul Shaikh , Tapobrata Sarkar

We propose a new marked two-point correlation function weighted by the global gravitational potential as a probe for testing gravity models. Using the LCDM model based on general relativity (GR) as a reference, we investigate two…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-24 Yizhao Yang , Yu Yu , Pengjie Zhang

The GRAVITY Collaboration achieved the remarkable detection of the orbital precession of the S2 star around the Galactic centre supermassive black hole, providing yet another proof of the validity of the General Relativity. The departure…

General Relativity and Quantum Cosmology · Physics 2021-11-18 Ivan de Martino , Riccardo della Monica , Mariafelicia de Laurentis

This study explores the link between Modified Gravity and modifications of phase space volume. Analyzing Fermi gas modifications {in the non-relativistic limit of the} Ricci-based gravities, we derive a generalized partition function in the…

General Relativity and Quantum Cosmology · Physics 2024-01-10 Aneta Wojnar

As is well known, a varying effective gravitational "constant" is one of the common features of most modified gravity theories. Of course, as a modified gravity theory, $f(T)$ theory is not an exception. Noting that the observational…

General Relativity and Quantum Cosmology · Physics 2012-08-31 Hao Wei , Hao-Yu Qi , Xiao-Peng Ma

The observed accelerated expansion of the Universe may be explained by dark energy or the breakdown of general relativity (GR) on cosmological scales. When the latter case, a modified gravity scenario, is considered, it is often assumed…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-04 Jiro Matsumoto , Teppei Okumura , Misao Sasaki

We explore observational constraints on possible deviations from Newtonian gravity by means of large-scale clustering of galaxies. We measure the power spectrum and the bispectrum of Sloan Digital Sky Survey galaxies and compare the result…

Astrophysics · Physics 2008-12-18 Akihito Shirata , Yasushi Suto , Chiaki Hikage , Tetsuya Shiromizu , Naoki Yoshida

In the pursuit of a general formulation for a modified gravitational theory at the non-relativistic level and as an alternative to the dark matter hypothesis, we construct a model valid over a wide variety of astrophysical scales. Through…

Astrophysics of Galaxies · Physics 2011-12-13 S. Mendoza , X. Hernandez , J. C. Hidalgo , T. Bernal

We consider a minimal fractional deformation of Newtonian gravity characterized by a single parameter $\alpha$. In the limit $\alpha \to 1$, the theory reduces to standard Newtonian gravity. Previous works showed that the $\Lambda$CDM…

General Relativity and Quantum Cosmology · Physics 2026-03-18 S. M. M. Rasouli

The modified gravity (MOG) theory is applied to the gravitational wave binary merger GW190814 to demonstrate that the modified Tolman-Oppenheimer-Volkoff equation for a neutron star can produce a mass $M=2.6 -2.7 M_\odot$, allowing for the…

General Relativity and Quantum Cosmology · Physics 2020-08-17 J. W. Moffat

We study some possible observational signatures of $R^n$ gravity at Galactic scales and how these signatures could be used for constraining this type of $f(R)$ gravity. For that purpose, we performed two-body simulations in $R^n$ gravity…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-06 D. Borka , P. Jovanović , V. Borka Jovanović , A. F. Zakharov

We use measurements of the growth of cosmic structure, as inferred from the observed evolution of the X-ray luminosity function (XLF) of galaxy clusters, to constrain departures from General Relativity (GR) on cosmological scales. We employ…

Astrophysics · Physics 2015-05-13 David Rapetti , Steven W. Allen , Adam Mantz , Harald Ebeling

Various experiments and observations have led researchers to suggest different bounds on fundamental constants like the fine-structure constant and the proton-to-electron mass ratio. These bounds differ mostly due to the energy scale of the…

General Relativity and Quantum Cosmology · Physics 2023-06-05 Surajit Kalita , Akhil Uniyal

The Parameterized Post-Newtonian (PPN) formalism offers an agnostic framework for evaluating theories of gravity that extend beyond General Relativity. Departures from General Relativity are represented by a set of dimensionless parameters…

Astrophysics of Galaxies · Physics 2025-02-19 Victor de Mora Losada , Riccardo Della Monica , Ivan de Martino , Mariafelicia De Laurentis

We discuss the galaxy clustering based on thermodynamics and statistical mechanics in the expanding universe in a modified theory of gravity. The modified general relativity (MGR) is developed using the regular line element field to…

General Physics · Physics 2023-02-15 Abdul W. Khanday , Sudhaker Upadhyay , Prince A. Ganai

We describe how a certain simple modification of general relativity, in which the local cosmological constant is allowed to depend on the space-time curvature, predicts the existence of halos of modified gravity surrounding…

General Relativity and Quantum Cosmology · Physics 2009-03-20 Kirill Krasnov , Yuri Shtanov