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Spherically symmetric dark energy structures are investigated in the framework of a generalized Chaplygin gas (GCG), which has an equation of state of the form $P = - A/\rho^{\alpha}} $. We also study these in a modified GCG equation of…

General Relativity and Quantum Cosmology · Physics 2007-06-07 Abiy G. Tekola

The consequences of taking the generalized Chaplygin gas as the dark energy constituent of the Universe on the gravitational waves are studied and the spectrum obtained from this model, for the flat case, is analyzed. Besides its importance…

General Relativity and Quantum Cosmology · Physics 2009-11-10 J. C. Fabris , S. V. B. Goncalves , M. S. dos Santos

The hypothesis that dark matter and dark energy are unified through the Chaplygin gas is reexamined. Using a generalization of the spherical model which incorporates effects of the acoustic horizon we show that an initially perturbative…

Astrophysics · Physics 2007-05-23 Neven Bilic , Robert J. Lindebaum , Gary B. Tupper , Raoul D. Viollier

We examine the properties of dark energy and dark matter through the study of the variation of the electromagnetic coupling. For concreteness, we consider the unification model of dark energy and dark matter, the generalized Chaplygin gas…

Astrophysics · Physics 2008-11-26 M. C. Bento , O. Bertolami , P. Torres

We model the cosmic medium as the mixture of a generalized Chaplygin gas and a pressureless matter component. Within a neo-Newtonian approach we compute the matter power spectrum. The 2dFGRS data are used to discriminate between unified…

Astrophysics · Physics 2015-05-13 J. C. Fabris , S. V. B. Goncalves , H. E. S. Velten , W. Zimdahl

We use the latest data to investigate observational constraints on the new generalized Chaplygin gas (NGCG) model. Using the Markov Chain Monte Carlo (MCMC) method, we constrain the NGCG model with the type Ia supernovae (SNe Ia) from…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Kai Liao , Yu Pan , Zong-Hong Zhu

We model the cosmic medium as the mixture of a generalized Chaplygin gas and a pressureless matter component. Within a neo-Newtonian approach (in which, different from standard Newtonian cosmology, the pressure enters the homogeneous and…

Astrophysics · Physics 2010-04-15 J. C. Fabris , S. V. B. Goncalves , H. E. S. Velten , W. Zimdahl

The generalized Chaplygin gas cosmology provides a prime example for the class of unified dark matter models, which substitute the two dark components of the standard cosmological LCDM concordance model by a single dark component. The…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-28 Ralf Aurich , Sven Lustig

In the past few years, the Chaplygin gas (CG) has been considered as an appealing candidate for unifying dark matter and dark energy into a single substance. This picture had to face several problems when trying to fit its predictions with…

Astrophysics · Physics 2009-11-10 F. Perrotta , S. Matarrese , M. Torki

The recent observational evidences for the present accelerated stage of the Universe have stimulated renewed interest for alternative cosmologies. In general, such models contain an unknown negative-pressure dark component that explains the…

Astrophysics · Physics 2009-11-07 J. V. Cunha , J. S. Alcaniz , J. A. S. Lima

We investigate the unification scenario provided by the generalised Chaplygin gas model (a perfect fluid characterized by an equation of state p = -A/\rho^{\alpha}). Our concerns lie with a possible tension existing between background…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-18 Juliano Pereira Campos , Júlio César Fabris , Rafael Perez , Oliver F. Piattella , Hermano Velten

The Modified Chaplygin Gas (MCG) model belongs to the class of a unified models of dark energy and dark matter. In this paper, we have modeled MCG in the framework of f-essence cosmology. By constructing an equation connecting the MCG and…

General Physics · Physics 2011-11-28 Mubasher Jamil , Yerlan Myrzakulov , Olga Razina , Ratbay Myrzakulov

$Om(z)$ is a diagnostic approach to distinguish dark energy models. However, there are few articles to discuss what is the distinguishing criterion. In this paper, firstly we smooth the latest observational $H(z)$ data using a…

General Relativity and Quantum Cosmology · Physics 2016-06-13 Jing-Zhao Qi , Ming-Jian Zhang , Wen-Biao Liu

We present a scalar-field formulation of the generalized Chaplygin gas (GCG) and modified Chaplygin gas (MCG) models, in which the cosmic fluid dynamics are reproduced by canonical Lagrangians with analytically derived energy density…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-23 Yi-Syuan Wu , Chuan-Jui Li , W. F. Kao

The fact that Einstein's equations connect the space-time geometry to the total matter content of the cosmic substratum, but not to individual contributions of the matter species, can be translated into a degeneracy in the cosmological dark…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-26 Rodrigo von Marttens , Dinorah Barbosa , Jailson Alcaniz

We have explored the possibility of the co-existence of two forms of dark energy in the form of an alternative Generalized Chaplygin Gas (GCG) along with a scalar field of field theoretic or extra dimensional origin in the background of a…

General Relativity and Quantum Cosmology · Physics 2026-01-28 Mahasweta Biswas , Rikpratik Sengupta , Ujjal Debnath

If the spatial section of the universe is multiply connected, repeated images or patterns are expected to be detected observationally. However, due to the finite distance to the last scattering surface, such pattern repetitions could be…

Astrophysics · Physics 2008-11-26 B. Mota , M. Makler , M. J. Reboucas

We discuss the prospects of using Gamma Ray Bursts (GRBs) as high-redshift distance estimators, and consider their use in the study of two dark energy models, the Generalized Chaplygin Gas (GCG), a model for the unification of dark energy…

Astrophysics · Physics 2007-05-23 O. Bertolami , P. T. Silva

We study the nonlinear regime of Unified Dark Energy models, using Generalized Chaplygin Gas cosmologies as a representative example, and introduce a new parameter characterizing the level of small scale clustering in these scenarios. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 P. P. Avelino , K. Bolejko , G. F. Lewis

The generalized Chaplygin gas (GCG) model in spatially flat universe is investigated. The cosmological consequences led by GCG model including the evolution of EoS parameter, deceleration parameter and dimensionless Hubble parameter are…

General Relativity and Quantum Cosmology · Physics 2011-06-10 M. Malekjani , A. Khodam-Mohammadi , N. Nazari-Pooya