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In the present work, we incorporate redshift-space distortion measurement to investigate the growth of large scale structure within the framework of multi-fluid cosmology in the context of modified Gauss-Bonnet gravity. Using three…

General Relativity and Quantum Cosmology · Physics 2025-08-18 Praveen Kumar Dhankar , Albert Munyeshyaka , Aritra Sanyal , Safiqul Islam , Farook Rahaman

The $\Lambda$CDM cosmological model successfully reproduces many aspects of the galaxy and structure formation of the universe. However, the growth of large-scale structures (LSSs) in the early universe is not well tested yet with…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-27 J. -W. Kim , M. Im , S. -K. Lee , A. C. Edge , M. Hyun , D. Kim , C. Choi , J. Hong , Y. Jeon , H. D. Jun , M. Karouzos , D. Kim , J. H. Kim , Y. Kim , W. -K. Park , Y. C. Taak , Y. Yoon

Accounting for large-scale structure in our universe will require not only reasonably accurate mathematical models of its cosmogony, topology and cosmology, but also a more deeper understanding of our fundamental physical concepts of space,…

Astrophysics · Physics 2016-08-30 Charles B. Leffert

The Lambda-Cold Dark Matter (LCDM) model agrees with most of the cosmological observations, but has some hindrances from observed data at smaller scales such as galaxies. Recently, Berezhiani and Khoury (2015) proposed a new theory…

General Relativity and Quantum Cosmology · Physics 2020-07-22 Shreya Banerjee , Sayantani Bera , David F. Mota

In the present work, we investigate cosmological perturbations of viscous modified chaplygin gas model. Using 1 + 3 covariant formalism, we define covariant and gauge invariant gradient variables, which after the application of scalar…

General Relativity and Quantum Cosmology · Physics 2024-12-31 Albert Munyeshyaka , Praveen Kumar Dhankar , Joseph Ntahompagaze

We expand previous works on the spherical `top-hat' collapse (SC-TH) framework in generalized Chaplygin gas (gCg) dominated universes. Here we allow the collapse in all energetic components within the system. We analyze the non-linear…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 R. A. A. Fernandes , J. P. M. de Carvalho , A. Yu. Kamenshchik , U. Moschella , A. da Silva

This paper investigates regarding cosmological implications of a bulk viscous modified Chaplygin gas (MCG) in (2+1)-dimensional Friedmann-Robertson-Walker spacetime, incorporating both theoretical analysis and observational constraints. We…

General Relativity and Quantum Cosmology · Physics 2025-04-29 Praveen Kumar Dhankar , Aritra Sanyal , Albert Munyeshyaka , Saibal Ray , Behnam Pourhassan

The concordance particle creation model - a class of $\Lambda(t)$CDM cosmologies - is studied using large scale structure (LSS) formation, with particular attention to the integrated Sachs-Wolfe (ISW) effect. The evolution of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-04 H. Velten , H. A. Borges , S. Carneiro , R. Fazolo , S. Gomes

We perform a validation of estimates of the growth rate of structure, described by the parameter combination $f\sigma_8$, in modified gravity cosmologies. We consider an analysis pipeline based on the redshift-space distortion modelling of…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-08 Alexandre Barreira , Ariel G. Sánchez , Fabian Schmidt

To better distinguish the nature of $H_0$ and $S_8$ tensions, it is necessary to separate the effects of expansion and the growth of structure. The growth index $\gamma$ was identified as the most important parameter that characterizes the…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-01 Cemsinan Deliduman , Furkan Şakir Dilsiz , Selinay Sude Binici

We use recently published redshift space distortion measurements of the cosmological growth rate, f sigma_8(z), to examine whether the linear evolution of perturbations in the R_h=ct cosmology is consistent with the observed development of…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-21 Fulvio Melia

One approach in modern cosmology consists in supposing that dark matter and dark energy are different manifestations of a single `quartessential' fluid. Following such idea, this work presents a study of the evolution of perturbations of…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Sandro Silva e Costa , Maximiliano Ujevic , Alesandro Ferreira dos Santos

We re-examine the growth index of the concordance $\Lambda$ cosmology in the light of the latest 6dF and {\em WiggleZ} data. In particular, we investigate five different models for the growth index $\gamma$, by comparing their cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Spyros Basilakos

In this paper we investigate the formation and propagation of singularities for the system for one-dimensional Chaplygin gas. In particular, under suitable assumptions we construct a physical solution with a new type of singularities called…

Analysis of PDEs · Mathematics 2013-11-15 De-Xing Kong , Changhua Wei , Qiang Zhang

Large-scale structure (LSS) studies in cosmology map and analyse matter in the Universe on the largest scales. Understanding the LSS can provide observational support for the Cosmological Principle (CP) and the Standard Cosmological Model…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-24 Alexia M. Lopez , Roger G. Clowes , Gerard M. Williger

Under the commonly used assumption that clumped objects can be well described by a spherical top-hat matter density profile, we investigate the evolution of the cosmic growth index in clustering dark energy (CDE) scenarios on sub-horizon…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-06 Ahmad Mehrabi , Mohammad Malekjani , Francesco Pace

We use the non-linear spherical model in cold dark matter (CDM) cosmologies with dark energy to investigate the effects of dark energy on the growth of structure and the formation of virialised structures. We consider dark energy models…

Astrophysics · Physics 2010-12-09 Cathy Horellou , Joel Berge

We study non-linear structure formation in high-resolution simulations of Early Dark Energy (EDE) cosmologies and compare their evolution with the standard LCDM model. Extensions of the spherical top-hat collapse model predict that the…

Astrophysics · Physics 2011-02-11 Margherita Grossi , Volker Springel

Accelerating Chaplygin gas combined with the decelerating braneworld Dvali-Gabadadze-Porrati (DGP) model can produce an overall accelerated expansion of the order of magnitude seen. Both models have similar asymptotic properties at early…

Astrophysics · Physics 2008-12-18 Matts Roos

The correspondence of the Gauss-Bonnet (GB) and its modification (MGB) models of dark energy with the standard and generalized Chaplygin gas-scalar field models (SCG and GCG) have been studied in a {\deg}at universe. The exact solution of…

General Relativity and Quantum Cosmology · Physics 2016-11-10 A. Khodam-Mohammadi , E. Karimkhani , A. Alaei