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Two different realistic $F(R)$ modified gravity models are considered in the framework of the Friedmann-Lemetre-Robertson-Walker universe. The parameters of these two models are adjusted to reach coherence with the most recent and accurate…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Antonio Jesús López-Revelles

In this work, our focus is on exploring the potential of current GRB measurements to provide reliable constraints on cosmological model parameters at high redshift. This work is divided into two parts. First, we calibrate the Amati relation…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-10 Darshan Kumar , Nisha Rani , Deepak Jain , Shobhit Mahajan , Amitabha Mukherjee

The growth rate of the large-scale structure of the universe has been advocated as the observable par excellence for testing gravity on cosmological scales. By considering linear-order deviations from General Relativity, we show that…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-12 Tessa Baker , Pedro G. Ferreira , Constantinos Skordis

An exact solution is obtained for the gravitational bending of light in static, spherically symmetric metrics which includes the Schwarzschild-de Sitter spacetime and also the Mannheim-Kazanas metric of conformal Weyl gravity. From the…

General Relativity and Quantum Cosmology · Physics 2017-01-06 Yen-Kheng Lim , Qing-hai Wang

We investigate the ability of state-of-the-art redshift-space distortions models for the galaxy anisotropic two-point correlation function \xi(r_p, \pi), to recover precise and unbiased estimates of the linear growth rate of structure f,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Sylvain de la Torre , Luigi Guzzo

We study the impact of lensing magnification on the observed three-dimensional galaxy clustering in redshift space. We used the RayGal suite of N-body simulations, from which we extracted samples of dark matter particles and haloes in the…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-25 Michel-Andrès Breton , Sylvain de la Torre , Jade Piat

Multiple modifications of general relativity (GR) have been proposed in the literature in order to understand the nature of the accelerated expansion of the Universe. However, thus far all the predictions of GR have been confirmed with…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-21 Alex Ho , Max Gronke , Bridget Falck , David F. Mota

Recent anomalies found in cosmological datasets such as the low multipoles of the Cosmic Microwave Background or the low redshift amplitude and growth of clustering measured by e.g., abundance of galaxy clusters and redshift space…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-24 Emilio Bellini , Antonio J. Cuesta , Raul Jimenez , Licia Verde

Future galaxy surveys hope to distinguish between the dark energy and modified gravity scenarios for the accelerating expansion of the Universe using the distortion of clustering in redshift space. The aim is to model the form and size of…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-06 Elise Jennings , Carlton M. Baugh , Silvia Pascoli

We explore cosmological perturbations in a modified Gauss-Bonnet f(G) gravity, using a 1+3 covariant formalism. In such a formalism, we define gradient variables to get perturbed linear evolution equations. We transform these linear…

General Relativity and Quantum Cosmology · Physics 2022-09-20 Albert Munyeshyaka , Joseph Ntahompagaze , Tom Mutabazi

Late time cosmic acceleration may be achieved by modifying gravity on large scales. This should also have consequences on the evolution of perturbations. We thus extend our study of exponential infrared $f(T)$ teleparallel gravity to…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-11 Mahmoud Hashim , Amr A. El-Zant , Waleed El Hanafy , Alexey Golovnev

Viable models of modified gravity designed to produce cosmic acceleration at the current epoch, closely mimic the $\Lambda$CDM model at the level of background cosmology. However, this degeneracy is generically broken at the level of linear…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-05 Alessandra Silvestri

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

The role of an exponential function of the scalar curvature in the modified gravity is analyzed. Two models are proposed. A toy model that complies with local and cosmological constraints and gives appropriate qualitative description of the…

General Relativity and Quantum Cosmology · Physics 2020-07-15 L. N. Granda

We compile a list of $14$ independent measurements of large-scale structure growth rate between redshifts $0.067 \leq z \leq 0.8$ and use this to place constraints on model parameters of constant and time-evolving general-relativistic dark…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Anatoly Pavlov , Omer Farooq , Bharat Ratra

We compare void size and clustering statistics for nDGP and $f(R)$ gravity models and GR using N-body simulations. We show how it is critical to consider the statistics derived from mock galaxy catalogs rather than the dark matter halos…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-21 Christopher Wilson , Rachel Bean

The combination of multiple cosmological probes can produce measurements of cosmological parameters much more stringent than those possible with any individual probe. We examine the combination of two highly correlated probes of late-time…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-08 Donnacha Kirk , Ofer Lahav , Sarah Bridle , Stephanie Jouvel , Filipe B. Abdalla , Joshua A. Frieman

This paper analyses the cosmological consequences of a modified theory of gravity whose action integral is built from a linear combination of the Ricci scalar $R$ and a quadratic term in the covariant derivative of $R$. The resulting…

General Relativity and Quantum Cosmology · Physics 2015-12-31 R. R. Cuzinatto , C. A. M. de Melo , L. G. Medeiros , P. J. Pompeia

In this lecture I address the issue of possible large distance modification of gravity and its observational consequences. Although, for the illustrative purposes we focus on a particular simple generally-covariant example, our conclusions…

High Energy Physics - Theory · Physics 2007-05-23 Gia Dvali

We present a formalism to calculate the non-linear matter power spectrum in modified gravity models that explain the late-time acceleration of the Universe without dark energy. Any successful modified gravity models should contain a…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-03 Kazuya Koyama , Atsushi Taruya , Takashi Hiramatsu