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We put constraints on the main cosmological parameters of different spatially flat cosmological models by combining the recent clustering results of XMM-Newton soft (0.5-2 keV) X-ray sources, which have a redshift distribution with median…

Astrophysics · Physics 2009-11-10 Spyros Basilakos , Manolis Plionis

Along with the construction of non-Lorentz-invariant effective field theories, recent studies which are based on geometric models of Finsler space-time become more and more popular. In this respect, the Finslerian approach to the problem of…

General Relativity and Quantum Cosmology · Physics 2015-06-03 V. Balan , G. Yu. Bogoslovsky , S. S. Kokarev , D. G. Pavlov , S. V. Siparov , N. Voicu

In this work we utilise the most recent publicly available type Ia supernova (SN Ia) compilations and implement a well formulated cosmological model based on Lema\^{i}tre-Tolman-Bondi metric in presence of cosmological constant $\Lambda$…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-24 Vladimir V. Luković , Balakrishna S. Haridasu , Nicola Vittorio

In this paper, we present an accelerating cosmological model by constraining the free parameters using the cosmological datasets in an extended symmetric teleparallel gravity for the flat and anisotropic space-time. We employ a time…

General Relativity and Quantum Cosmology · Physics 2023-06-27 S. A. Narawade , M. Koussour , B. Mishra

The latest improvements in the scale and calibration of Type Ia supernovae catalogues allow us to constrain the specific nature and evolution of dark energy through its effect on the expansion history of the universe. We present the results…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-05 Toby Lovick , Suhail Dhawan , Will Handley

We investigate a two-parameter extension of the $\Lambda_{\rm s}$CDM model by allowing variations in the effective number of neutrino species $N_{\rm eff}$ and their total mass $\sum m_\nu$. Our motivation is twofold: (i) to examine whether…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 Anita Yadav , Suresh Kumar , Cihad Kibris , Ozgur Akarsu

We develop a new approach to building cosmological models, in which small pieces of perturbed Minkowski space are joined together at reflection-symmetric boundaries in order to form a global, dynamical space-time. Each piece of this…

General Relativity and Quantum Cosmology · Physics 2016-04-12 Viraj A. A. Sanghai , Timothy Clifton

This work explores a Standard Model (S.M.) extension possibility, that violates Lorentz invariance, preserving the space-time isotropy and homogeneity. In this sense HMSR represents an attempt to introduce an isotropic Lorentz Invariance…

High Energy Physics - Theory · Physics 2019-10-03 M. D. C. Torri , V. Antonelli , L. Miramonti

According to standard cosmology, the universe is homogeneous and isotropic at large scales. However, some anisotropies can be observed at the local scale in the universe through various ways. Here we have studied the Bianchi type I model…

General Relativity and Quantum Cosmology · Physics 2022-09-12 Pranjal Sarmah , Umananda Dev Goswami

The onset of dark energy domination depends on the particular gravitational theory driving the cosmic evolution. Model independent techniques are crucial to test both the present $\Lambda$CDM cosmological paradigm and alternative theories,…

General Relativity and Quantum Cosmology · Physics 2017-01-04 Álvaro de la Cruz-Dombriz , Peter K. S. Dunsby , Orlando Luongo , Lorenzo Reverberi

Inhomogeneous universe models have been proposed as an alternative explanation for the apparent acceleration of the cosmic expansion that does not require dark energy. In the simplest class of inhomogeneous models, we live within a large,…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Michael Blomqvist , Edvard Mortsell

Cardassian models are an alternative to general relativity which have been proposed as an approach to explaining accelerated cosmic expansion while avoiding directly introducing dark energy. They are generally formulated only in the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Nikolaus Berndt , Alan D. Rendall

We look at observational constraints on the thawing class of scalar field models proposed to explain the late time acceleration of the universe. Using the recently introduced `Statefinder Hierarchy', we compare these thawing class of models…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Gaveshna Gupta , Subhabrata Majumdar , Anjan A Sen

We investigate the global texture model of structure formation in cosmogonies with non-zero cosmological constant for different values of the Hubble parameter. We find that the absence of significant acoustic peaks and little power on large…

Astrophysics · Physics 2009-10-31 Ruth Durrer , Martin Kunz , Alessandro Melchiorri

In this paper, we have explored the field equations of f(T, B) gravity as an extension of teleparallel gravity in an isotropic and homogeneous space time. In the basic formalism developed, the dynamical parameters are derived by…

General Relativity and Quantum Cosmology · Physics 2024-09-27 S. A. Kadam , Jackson Levi Said , B. Mishra

A powerful result in theoretical cosmology states that a subset of anisotropic Bianchi models can be seen as the homogeneous limit of (standard) linear cosmological perturbations. Such models are precisely those leading to Friedmann…

General Relativity and Quantum Cosmology · Physics 2025-06-03 Thiago S. Pereira , Cyril Pitrou

We present an analysis of an $f(T, \mathcal{T})$ extension of the Teleparallel Equivalent of General Relativity, where $T$ denotes the torsion and $\mathcal{T}$ the trace of the energy-momentum tensor. This extension includes non--minimal…

General Relativity and Quantum Cosmology · Physics 2016-07-27 Diego Saez-Gomez , C. Sofia Carvalho , Francisco S. N. Lobo , Ismael Tereno

We analyse the full shape of anisotropic clustering measurements from the extended Baryon Oscillation Spectroscopic survey (eBOSS) quasar sample together with the combined galaxy sample from the Baryon Oscillation Spectroscopic Survey…

We investigate two dark energy cosmological models (i.e., the $\Lambda$CDM and $\phi$CDM models) with massive neutrinos assuming two different neutrino mass hierarchies in both the spatially flat and non-flat scenarios, where in the…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-15 Yun Chen , Bharat Ratra , Marek Biesiada , Song Li , Zong-Hong Zhu

I deduce an exact and analytic Bianchi type I solution of Einsteins field equations, which generalizes the isotropic LambdaCDM universe model to a corresponding model with anisotropic expansion. The main point of the article is to present…

General Relativity and Quantum Cosmology · Physics 2024-06-17 Øyvind G. Grøn
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