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When it comes to searches for extensions to general relativity, large efforts are being dedicated to accurate predictions for the power spectrum of density perturbations. While this observable is known to be sensitive to the gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-08 Claudio Llinares , Nuala McCullagh

Motivated by the possibility that the fundamental ``constants'' of nature could vary with time, this paper considers the long term evolution of white dwarf stars under the combined action of proton decay and variations in the gravitational…

Astrophysics · Physics 2009-11-13 Jacob A. Ketchum , Fred C. Adams

Modified theories of gravity have received a renewed interest due to their ability to account for the cosmic acceleration. In order to satisfy the solar system tests of gravity, these theories need to include a screening mechanism that…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-15 Jeremy Sakstein , Bhuvnesh Jain , Vinu Vikram

We study the effect of modifications to General Relativity on large scale weak lensing observables. In particular, we consider three modified gravity scenarios: f(R) gravity, the DGP model, and TeVeS theory. Weak lensing is sensitive to the…

Astrophysics · Physics 2008-11-26 Fabian Schmidt

We study the growth of structures in modified gravity models where the Poisson equation and the relationship between the two Newtonian potentials are modified by explicit functions of space and time. This parameterisation applies to the…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-24 Philippe Brax , Patrick Valageas

Theories with varying gravitational constant $G$ have been studied since long time ago. Among them, the most promising candidates as alternatives of the standard General Relativity are known as scalar-tensor theories. They provide…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Diego F. Torres

The lack of detection of supersymmetric particles is leading to look at alternative avenues for explaining dark matter's effects. Among them, modified theories of gravity may play an important role accounting even for both dark components…

General Relativity and Quantum Cosmology · Physics 2020-02-19 Ivan de Martino

In this work we investigate the equilibrium configurations of white dwarfs in a modified gravity theory, na\-mely, $f(R,T)$ gravity, for which $R$ and $T$ stand for the Ricci scalar and trace of the energy-momentum tensor, respectively.…

General Relativity and Quantum Cosmology · Physics 2017-12-20 G. A. Carvalho , R. V. Lobato , P. H. R. S. Moraes , José D. V. Arbañil , R. M. Marinho , E. Otoniel , M. Malheiro

In recent years, the idea of sub- and super-Chandrasekhar limiting mass white dwarfs (WDs), which are potential candidates to produce under- and over-luminous type Ia supernovae, respectively, has been a key interest in the scientific…

General Relativity and Quantum Cosmology · Physics 2022-02-04 Surajit Kalita , Lupamudra Sarmah

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 investigate realistic models of compact objects, focusing on neutron and strange stars, composed by dense matter and dark energy in the form of a simple fluid or scalar field interacting with matter. For the dark energy component, we use…

General Relativity and Quantum Cosmology · Physics 2023-08-01 Artyom V. Astashenok , Sergey D. Odintsov , Vasilis K. Oikonomou

It has been suggested that Einstein's theory of General Relativity can be modified to accomodate mismatches between the gravitational field and luminous matter on a wide range of scales. Covariant theories of modified gravity generically…

Astrophysics · Physics 2009-03-31 P. G Ferreira , C. Skordis , C. Zunckel

The advancement of astronomical observations opens the possibility of testing our current understanding of gravitational theory in the strong-field regime and probing any deviation from general relativity. We explore to what extent compact…

General Relativity and Quantum Cosmology · Physics 2024-03-29 M. D. Danarianto , I. Prasetyo , A. Suroso , B. E. Gunara , A. Sulaksono

We offer a discussion on the strong field regime predictions of two families of theories that deviate from General Relativity in different aspects: $f(R)$-gravity and Scalar-Tensor-Vector Gravity (STVG). We discuss astrophysical effects in…

General Relativity and Quantum Cosmology · Physics 2020-01-06 Daniela Pérez , Gustavo E. Romero

In a modified gravity theory, the propagation equation of gravitational waves will be presented in a non-standard way. Therefore this tenor mode perturbation of time-space, as a complement to the scalar mode perturbation, provides a unique…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Lixin Xu

The distribution of galaxies provides an ideal laboratory to test for deviations from General Relativity. In particular, redshift-space distortions are commonly used to constrain modifications to the Poisson equation, which governs the…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-19 Sveva Castello , Nastassia Grimm , Camille Bonvin

This work is aimed to explore the dark dynamical effects of $f(R,T)$ modified gravity theory on the dynamics of compact celestial star. We have taken the interior geometry as spherical star which is filled with imperfect fluid distribution.…

General Relativity and Quantum Cosmology · Physics 2017-11-09 M. Z. Bhatti , Z. Yousaf , M. Ilyas

We review the recent literature on modified theories of gravity in the Palatini approach. After discussing the motivations that lead to consider alternatives to Einstein's theory and to treat the metric and the connection as independent…

General Relativity and Quantum Cosmology · Physics 2011-05-09 Gonzalo J. Olmo

Recent literature has seen an ongoing discussion on the limiting mass of strongly magnetized white dwarfs, since such objects may prove to be a source of over-luminous type-Ia supernovae. In an earlier paper, we have presented the…

Solar and Stellar Astrophysics · Physics 2016-01-20 Prasanta Bera , Dipankar Bhattacharya

Many theories of modified gravity, including the well studied Horndeski models, are characterized by a screening mechanism that ensures that standard gravity is recovered near astrophysical bodies. In a recently introduced class of…

General Relativity and Quantum Cosmology · Physics 2015-06-11 Ryo Saito , Daisuke Yamauchi , Shuntaro Mizuno , Jérôme Gleyzes , David Langlois