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Related papers: Observational Constraints on Model with specific q

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It has been proposed that the observed dark energy can be explained away by the effect of large-scale nonlinear inhomogeneities. In the present paper we discuss how observations constrain cosmological models featuring large voids. We start…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 Valerio Marra , Alessio Notari

Cosmological models with Lagrange multipliers are appealing because they could explain the behaviour of the dark sector in a unified way. In this work we analyse extensions to the "Dust of Dark Energy model" proposed in arXiv:1003.5751 by…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Antonella Cid , Pedro Labrana

We place new constraints on the primordial local non-Gaussianity parameter f_NL using recent Cosmic Microwave Background anisotropy and galaxy clustering data. We model the galaxy power spectrum according to the halo model, accounting for a…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Francesco De Bernardis , Paolo Serra , Asantha Cooray , Alessandro Melchiorri

In this work, we investigate a cosmological scenario with a time-dependent cosmological constant $\Lambda$(t) within the spatially flat Friedmann-Lema\^itre-Robertson-Walker (FLRW) framework. Here we study a power-law $\Lambda(t)$CDM model…

General Relativity and Quantum Cosmology · Physics 2025-10-28 Archana Dixit , Manish Yadav , Anirudh Pradhan , M. S. Barak

In this paper, we study the cosmic constraint to $w$CDM model via $118$ strong gravitational lensing systems which are complied from SLACS, BELLS, LSD and SL2S surveys, where the ratio between two angular diameter distances $D^{obs} =…

General Relativity and Quantum Cosmology · Physics 2017-03-15 Jie An , Baorong Chang , Lixin Xu

Recent supernovae of type Ia measurements and other astronomical observations suggest that our universe is in accelerating phase of evolution at the present epoch. While a dark energy of unknown form is usually proposed as the most feasible…

Astrophysics · Physics 2008-11-26 Andrzej Borowiec , Wlodzimierz Godlowski , Marek Szydlowski

In the context of f(R, T) gravity theory for the flat Friedmann Lemaitre Robertson Walker (FLRW) model, the accelerating expansion of the universe is investigated using a specific form of the emergent Hubble parameter. Datasets from H(z),…

General Relativity and Quantum Cosmology · Physics 2025-01-16 N. Myrzakulov , S. H. Shekh , Anirudh Pradhan , Archana Dixit

Extended teleparallel gravity, characterized by $F(Q)$ function where $Q$ is the non-metricity scalar, is one of the most promising approaches to general relativity. In this paper, we reexamine a specific dynamical dark energy model, which…

General Relativity and Quantum Cosmology · Physics 2024-08-14 Omar Enkhili , Safae Dahmani , Dalale Mhamdi , Taoufik Ouali , Ahmed Errahmani

Since viable $f(R)$ gravity models must reconcile early-universe inflation with late-time acceleration, we specifically study the dynamical behavior of such a theory during the matter-dominated to dark-energy-dominated transition epoch. By…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-03 Siqi He , Weiqiang Yang , Hangyi Jin

Understanding the accelerating expansion of the Universe remains a fundamental challenge in modern cosmology. In this paper, we investigate a cosmological model parametrized by a generalized variable deceleration parameter to elucidate the…

General Relativity and Quantum Cosmology · Physics 2023-09-29 M. Koussour , N. Myrzakulov , Alnadhief H. A. Alfedeel , F. Awad , M. Bennai

This paper investigates the flat Friedmann-Lema$\hat{\imath}$tre-Robertson-Walker (FLRW) cosmological model using a suitable parameterization represented as a differential equation concerning the energy density of the scalar field,…

General Relativity and Quantum Cosmology · Physics 2024-04-30 J. K. Singh , Shaily , Harshna Balhara , Sushant G. Ghosh , Sunil D. Maharaj

We use observational data from Supernovae (SNIa) Pantheon sample, as well as from direct measurements of the Hubble parameter from the cosmic chronometers (CC) sample, in order to extract constraints on the scenario of Barrow holographic…

General Relativity and Quantum Cosmology · Physics 2020-06-25 Fotios K. Anagnostopoulos , Spyros Basilakos , Emmanuel N. Saridakis

In this paper, we examine the accelerated expansion of the Universe at late-time in the framework of $f\left( Q\right) $ gravity theory in which the non-metricity scalar $Q$ describes the gravitational interaction. To this, we propose a new…

General Relativity and Quantum Cosmology · Physics 2023-02-21 M. Koussour , S. K. J. Pacif , M. Bennai , P. K. Sahoo

A simple speed-up cosmology model is proposed to account for the dark energy puzzle. We condense contributions from dark energy and curvature term into one effective parameter in order to reduce parameter degeneracies and to find any…

Astrophysics · Physics 2007-10-10 Xin-He Meng , Meng Su , Zheng Wang

It has been widely shown that the cosmological parameters and dark energy can be constrained by using data from type-Ia supernovae (SNe Ia), the cosmic microwave background (CMB) anisotropy, the baryon acoustic oscillation (BAO) peak from…

Astrophysics · Physics 2009-06-23 F. Y. Wang , Z. G. Dai , Zong-Hong Zhu

We compute the constraints on a ``standard'' 10 parameter cold dark matter (CDM) model from the most recent CMB and data and other observations, exploring 30 million discrete models and two continuous parameters. Our parameters are the…

Astrophysics · Physics 2009-09-25 Max Tegmark , Matias Zaldarriaga

The decaying vacuum model (DV), treating dark energy as a varying vacuum, has been studied well recently. The vacuum energy decays linearly with the Hubble parameter in the late-times, $\rho_\Lambda(t) \propto H(t)$, and produces the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 M. L. Tong , H. Noh

We present a new model-independent strategy for testing the Friedmann-Lema\^{\i}tre-Robertson-Walker metric and constraining cosmic curvature, based on future time delay measurements of strongly lensed quasar-elliptical galaxy systems from…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-20 Kai Liao , Zhengxiang Li , Guo-Jian Wang , Xi-Long Fan

We investigate two new observational perspectives in the context of torsional gravitational modification of general relativity, i.e., the $f(T)$ gravity: i) We use Pantheon data of type Ia supernovae motivated by a time variation of the…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-21 Suresh Kumar , Rafael C. Nunes , Priya Yadav

We investigate the influence of bulk viscosity on late-time cosmic acceleration within an extended $f(Q, L_m)$ gravity framework, where the non-metricity $Q$ is non-minimally coupled with the matter Lagrangian $L_m$. Analyzing the function…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-05 Y. Myrzakulov , O. Donmez , M. Koussour , S. Muminov , I. Y. Davletov , J. Rayimbaev