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The tension between the Hubble constant obtained from the local measurements and from cosmic microwave background (CMB) measurements motivated us to consider the cosmological model beyond $\Lambda$CDM one. We investigate the cosmology in…

General Relativity and Quantum Cosmology · Physics 2022-06-15 Jing Li , Yongxiang Zhou , Xun Xue

In this paper, we study the dynamical behaviour of the Universe in the $F(R,G)$ theory of gravity, where $R$ and $G$ respectively denote the Ricci scalar and Gauss-Bonnet invariant. Our wide analysis encompasses the energy conditions,…

General Relativity and Quantum Cosmology · Physics 2022-04-22 Santosh V. Lohakare , S. K. Tripathy , B. Mishra

Exact cosmological models for a scalar field in Lyra geometry are studied in the presence of a time-varying effective cosmological term originated from the specific interaction of an auxiliary $\Lambda$ - term with the displacement vector.…

General Relativity and Quantum Cosmology · Physics 2014-04-25 V. K. Shchigolev

In this paper, a cosmological model of the Universe is presented in $f(Q,T)$ gravity and the parameters are constrained by cosmological data sets. Initially, a generalised form of $f(Q,T)$ model is used as $f(Q,T)=-\lambda_{1}…

General Relativity and Quantum Cosmology · Physics 2024-03-21 A. S. Agrawal , B. Mishra , S. K. Tripathy

In this paper, we study quintessence cosmology with an effective $\Lambda$-term in Lyra manifold. We consider three different models by choosing variable $\Lambda$ depend on time, the Hubble parameter and the energy density of dark matter…

General Relativity and Quantum Cosmology · Physics 2015-10-28 M. Khurshudyan , A. Pasqua , J. Sadeghi , H. Farahani

We argued in a previous paper [R. A. Vanderveld et al. 2006, arXiv:astro-ph/0602476] that negative deceleration parameters at the center of symmetry in Lemaitre-Tolman-Bondi cosmological models can only occur if the model is not smooth at…

Cosmology and Nongalactic Astrophysics · Physics 2009-05-08 R. Ali Vanderveld , Eanna E. Flanagan , Ira Wasserman

New systematic classification of cosmological models of the present Universe is introduced. After making the comparison of these models with all existing observational data three viable models remain: the cold dark matter model with the…

Astrophysics · Physics 2007-05-23 A. A. Starobinsky

In the early seventies, Alan Sandage defined cosmology as the search for two numbers: Hubble parameter ${{H}_{0}}$ and deceleration parameter ${{q}_{0}}$. The first of the two basic cosmological parameters (the Hubble parameter) describes…

General Relativity and Quantum Cosmology · Physics 2015-07-01 Yu. L. Bolotin , V. A. Cherkaskiy , O. A. Lemets , D. A. Yerokhin , L. G. Zazunov

We extend the results of a previous paper where a model of interacting dark energy, with a cosmological term decaying linearly with the Hubble parameter, is tested against the observed mass power spectrum. In spite of the agreement with…

Astrophysics · Physics 2008-12-30 H. A. Borges , S. Carneiro , J. C. Fabris

To find more deliberate f(R,T) cosmological solutions, we proceed our previous paper further by studying some new aspects of the considered models via investigation of some new cosmological parameters/quantities to attain the most…

General Relativity and Quantum Cosmology · Physics 2017-05-23 Hamid Shabani , Mehrdad Farhoudi

In this present work, we try to build up a cosmological model using a non-canonical scalar field within the framework of a spatially flat FRW space-time. In this context, we have considered four different parametrizations of the equation of…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Abdulla Al Mamon , Sudipta Das

We consider weak gravity at accelerations $\alpha<a_H$ when Rindler and cosmological horizon collude at $R_H=c/H$, where $c$ is the velocity of light and $H$ is the Hubble parameter. This is manifest in reduced inertia $m$, below the value…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-18 Maurice H. P. M. van Putten

We use updated Hubble parameter and baryon acoustic oscillation data, as well as other lower-redshift Type Ia supernova, Mg II reverberation-measured quasar, quasar angular size, H II starburst galaxy, and Amati-correlated gamma-ray burst…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-31 Shulei Cao , Bharat Ratra

Large-scale bulk peculiar motions introduce a characteristic length scale, inside which the local kinematics are dominated by peculiar-velocity perturbations rather than by the background Hubble expansion. Regions smaller than the…

General Relativity and Quantum Cosmology · Physics 2022-06-29 Christos G. Tsagas

Constraining the dark energy deceleration parameter is one of the fascinating topics in the recent cosmological paradigm. This work aims to reconstruct the dark energy using parametrization of the deceleration parameter in a flat FRW…

General Relativity and Quantum Cosmology · Physics 2023-09-26 Amine Bouali , Himanshu Chaudhary , Ujjal Debnath , Alok Sardar , G. Mustafa

The results of different analyses of the dynamical parameters of the Universe are converging towards agreement. Remaining disagreements reflect systematic errors coming either from the observations or from differences in the methods of…

Astrophysics · Physics 2007-05-23 Matts Roos , S. M. Harun-or-Rashid

Time delays between multiple images of lensed sources can probe the geometry of the universe. We propose a novel method based on free-form modelling of gravitational lenses to estimate time-delay distances and, in turn, cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Mauro Sereno , Danuta Paraficz

We study cosmological evolution in a flat FLRW spacetime in the context of modified STEGR gravity or $f(Q)$, using an exponential two-parameter model which represents a smooth perturbative expansion around the $\Lambda$CDM model. The…

General Relativity and Quantum Cosmology · Physics 2025-04-15 Ivan R. Vasquez , A. Oliveros

Nowadays, according to the observational evidences the curvature parameter of the universe is neglected and spatially flat FLRW model is on the top of interest for cosmologists. However, due to some discrepancies between $\Lambda$-CDM model…

General Relativity and Quantum Cosmology · Physics 2021-09-30 Ali A. Asgari , Amir H. Abbassi

A cosmological model in Lyra's geometry are studied under the assumption that an effective cosmological term is appeared in the field equations as the result of interaction between the displacement vector field and an auxiliary $ \Lambda $…

General Relativity and Quantum Cosmology · Physics 2013-10-31 V. K. Shchigolev