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In this paper, a unified dark fluid with constant adiabatic sound speed is decomposed into cold dark matter interacting with vacuum energy. Based on Markov chain Monte Carlo method, we constrain this model by jointing the geometry and…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-18 Weiqiang Yang , Lixin Xu , Yuting Wang , Yabo Wu

We study a uniform and isotropic cosmology with a decaying vacuum energy density, in the realm of a model with a time varying gravitational "constant". We show that, for late times, such a cosmology is in accordance with the observed values…

General Relativity and Quantum Cosmology · Physics 2016-11-09 Saulo Carneiro

We use different combinations of data samples to investigate the new generalized Chaplygin gas (NGCG) model in the context of dark energy (DE) cosmology. Using the available cosmological data, we put constraints on the the free parameters…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-19 Fataneh Salahedin , Reza Pazhouhesh , Mohammad Malekjani

We determine the range of parameter space of Interacting Quintessence Models that best fits the recent WMAP measurements of Cosmic Microwave Background temperature anisotropies. We only consider cosmological models with zero spatial…

Astrophysics · Physics 2009-11-10 German Olivares , Fernando Atrio-Barandela , Diego Pavon

The modified Chaplygin gas (MCG) cosmological model is derived by using the geometrothermodynamics (GTD) formalism. We show that the MCG corresponds to a system with internal thermodynamic interaction and describes the current accelerated…

General Relativity and Quantum Cosmology · Physics 2019-01-15 Hachemi B. Benaoum , Hernando Quevedo

In unparticle dark matter (unmatter) models the equation of state of the unmatter is given by $p=\rho/(2d_U+1)$, where $d_U$ is the scaling factor. Unmatter with such equations of state would have a significant impact on the expansion…

Astrophysics · Physics 2008-12-18 Yan Gong , Xuelei Chen

We constrain two vacuum decay models ($\Lambda(t)$CDM, proposed by the authors of~\cite{Brito:2024bhh}) utilizing the baryon acoustic oscillations (BAO) data released by the Dark Energy Spectroscopic Instrument (DESI), distance prior from…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-11 Yupeng Yang , Yicheng Wang , Xinyi Dai

The type Ia supernovae observational data are used to estimate the parameters of a cosmological model with cold dark matter and the Chaplygin gas. The Chaplygin gas model depends essentially on four parameters: the Hubble constant, the…

Astrophysics · Physics 2009-12-30 R. Colistete , J. C. Fabris , S. V. B. Gonçalves , P. E. de Souza

The cosmological model with an interaction between dynamical quintessence dark energy and cold dark matter is considered. Evolution of a dark energy equation of state parameter is defined by a dark energy adiabatic sound speed and a dark…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-08 Roman Neomenko

We consider a generic cosmological model which allows for non-gravitational direct couplings between dark matter and dark energy. The distinguishing cosmological features of these couplings can be probed by current cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-17 Carsten van de Bruck , Jurgen Mifsud

We study cosmological perturbations in the context of an interacting dark energy model, in which the cosmological term decays linearly with the Hubble parameter, with concomitant matter production. A previous joint analysis of the…

Astrophysics · Physics 2008-11-26 H. A. Borges , S. Carneiro , J. C. Fabris , C. Pigozzo

We investigate a kind of interacting Chaplygin gas model in which the Chaplygin gas plays the role of dark energy and interacts with cold dark matter particles. We find that there exists a stable scaling solution at late times with the…

Astrophysics · Physics 2009-11-13 Hongsheng Zhang , 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 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

In this paper, we study cosmologies containing the reduced modified Chaplygin gas (RMCG) fluid which is reduced from the modified Chaplygin gas $p=A\rho-B\rho^{-\alpha}$ for the value of $\alpha=-1/2$. In this special case, dark…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Jianbo Lu , Danhua Geng , Lixin Xu , Yabo Wu , Molin Liu

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 use the Markov Chain Monte Carlo method to investigate a global constraints on the modified Chaplygin gas (MCG) model as the unification of dark matter and dark energy from the latest observational data: the Union2 dataset of type…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-12 Jianbo Lu , Lixin Xu , Yabo Wu , Molin Liu

We review the main features of the generalized Chaplygin gas (GCG) proposal for unification of dark energy and dark matter and discuss how it admits an unique decomposition into dark energy and dark matter components once phantom-like dark…

Astrophysics · Physics 2017-08-23 Orfeu Bertolami

We have investigated constraints on the coupling between dark matter and the interacting Chaplygin gas. Our results indicate that the coupling constant $c$ between these two entities can take arbitrary values, which can be either positive…

Astrophysics · Physics 2009-06-23 Mubasher Jamil , Muneer Ahmad Rashid

We consider a universe filled by a modified generalized Chaplygin gas together with a pressureless dark matter component. We get a thermodynamical interpretation for the modified generalized Chaplygin gas confined to the apparent horizon of…

General Relativity and Quantum Cosmology · Physics 2016-05-18 H. Ebadi , H. Moradpour

The goal of this paper is to study new cosmological models where the dark energy is a varying Chaplygin gas. This specific dark energy model with non-linear EoS had been often discussed in modern cosmology. Contrary to previous studies, we…

General Relativity and Quantum Cosmology · Physics 2021-05-04 M. Khurshudyan , R. Myrzakulov
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