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The irrotational Bianchi V cosmological model under the influence of both shear and bulk viscosity, together with heat flux, has been studied. Exact solutions for the model are obtained with three physically viable assumptions. The first…

General Relativity and Quantum Cosmology · Physics 2019-12-09 A. Banerjee , Abhik Kumar Sanyal

In the present work we have searched the existence of the late time acceleration of the Universe. The matter source that is responsible for the late time acceleration of the Universe consists of cosmic fluid with the equation of state…

General Physics · Physics 2013-01-29 Anil Kumar Yadav , Farook Rahaman , Saibal Ray , G. K. Goswami

In this paper, we have analyzed the significance of bulk viscosity in an axially symmetric Bianchi type-I model to study the accelerated expansion of the universe. We have considered four bulk viscosity parameterizations for the…

General Relativity and Quantum Cosmology · Physics 2022-12-21 Archana Dixit , Anirudh Pradhan , Vinod Kumar Bhardwaj , A. Beesham

Correlations of galaxy ellipticities with large-scale structure, due to galactic tidal interactions, provide a potentially significant contaminant to measurements of cosmic shear. However, these intrinsic alignments are still poorly…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-21 Patricia Larsen , Anthony Challinor

Anisotropies generically dominate the earliest stages of expansion of a homogeneous universe. They are particularly relevant in bouncing models, since shears grow in the contracting phase of the cosmos, making the isotropic situation…

General Relativity and Quantum Cosmology · Physics 2020-09-04 Ivan Agullo , Javier Olmedo , V. Sreenath

In this brief review I will touch upon the main points and thends of observational and theoretical cosmology, that influence and change today our understanding of the Universe.

Astrophysics · Physics 2007-05-23 Vladimir N. Lukash

A new class of exact solutions of Einstein's field equations with perfect fluid for an LRS Bianchi type-I spacetime is obtained by using a time dependent deceleration parameter. We have obtained a general solution of the field equations…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Anirudh Pradhan , S. Otarod

We infer gravitational lensing shear and convergence fields from galaxy ellipticity catalogs under a spatial process prior for the lensing potential. We demonstrate the performance of our algorithm with simulated Gaussian-distributed…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-19 Michael D. Schneider , Karen Y. Ng , William A. Dawson , Philip J. Marshall , Joshua Meyers , Deborah J. Bard

We use our N\"other Symmetry Approach to study the Einstein equations minimally coupled with a scalar field, in the case of Bianchi universes of class A and B. Possible cases, when such symmetries exist, are found and two examples of exact…

General Relativity and Quantum Cosmology · Physics 2011-05-19 Salvatore Capozziello , Giuseppe Marmo , Claudio Rubano , Paolo Scudellaro

The approach of a quantum state to a cosmological singularity is studied through the evolution of its moments in a simple version of a Bianchi I model. In spite of the simplicity, the model exhibits several instructive and unexpected…

General Relativity and Quantum Cosmology · Physics 2020-06-03 Ana Alonso-Serrano , Martin Bojowald , David Brizuela

A cosmological model, in which the cosmic microwave background (CMB) is a thermal radiation of intergalactic dust instead of a relic radiation of the Big Bang, is revived and revisited. The model suggests that a virtually transparent local…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-30 Vaclav Vavrycuk

The Universe is the grandest conceivable scale on which the human mind can strive to understand nature. The amazing aspect of cosmology, the branch of science that attempts to understand the origin and evolution of the Universe, is that it…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-19 Tarun Souradeep

As recently shown by Viola et al., the common (KSB) method for measuring weak gravitational shear creates a non-linear relation between the measured and the true shear of objects. We investigate here what effect such a non-linear…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Matthias Bartelmann , Massimo Viola , Peter Melchior , Björn M. Schäfer

Recent Wilkinson Microwave Anisotropy Probe (WMAP) data confirm the Cosmic Microwave Background (CMB) quadrupole anomaly. We further elaborate our previous proposal that the quadrupole power can be naturally suppressed in axis-symmetric…

Astrophysics · Physics 2008-11-26 L. Campanelli , P. Cea , L. Tedesco

We derive the evolution equations for the spectra of the Universe. Here "spectra" means the eigenvalues of the Laplacian defined on a space, which contain the geometrical information on the space. These equations are expected to be useful…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Masafumi Seriu

We implement Polymer Quantum Mechanics on the Hamiltonian formulation of the isotropic Universe in both the representations of the standard Ashtekar-Barbero-Immirzi connection and of a new generalized coordinate conjugate to the Universe…

General Relativity and Quantum Cosmology · Physics 2023-02-01 Gabriele Barca , Eleonora Giovannetti , Federico Mandini , Giovanni Montani

In this review, the formation, evolution, and decay of the large-scale structure of the Universe is discussed in the context of observational data, numerical simulations, and the Cosmological Standard Model (CSM). Problems concerning…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-04 V. N. Lukash , E. V. Mikheeva , A. M. Malinovsky

We investigate cosmologies where the accelerated expansion of the Universe is driven by a field with an anisotropic equation of state. We model such scenarios within the Bianchi I framework, introducing two skewness parameters to quantify…

Astrophysics · Physics 2009-06-23 Tomi Koivisto , David F. Mota

In order to reach the required performance of Stage-III and IV weak lensing surveys, cosmic shear measurements have to rely on external simulations to calibrate residual biases. Over the years, several techniques have been developed to…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-11 G. Congedo , A. N. Taylor

Gravitational lensing shear has the potential to be the most powerful tool for constraining the nature of dark energy. However, accurate measurement of galaxy shear is crucial and has been shown to be non-trivial by the Shear TEsting…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 L. M. Voigt , S. L. Bridle