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相关论文: Variable Chaplygin Gas: Constraints from Supernova…

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We use the hybrid model of bulk viscosity and generalized chaplygin gas (GCG), named the viscous generalized chaplygin gas (VGCG) model, which is thought to be an alternate dark fluid of the universe. We explore the dynamics of the VGCG…

广义相对论与量子宇宙学 · 物理学 2023-03-13 Gaurav N. Gadbail , Simran Arora , P. K. Sahoo

The supernova type Ia observational data are fitted using a model with cold dark matter and the Chaplygin gas. The Chaplygin gas, which is characterized by a negative pressure varying with the inverse of density, represents in this model…

天体物理学 · 物理学 2007-05-23 J. C. Fabris , S. V. B. Goncalves , P. E. de Souza

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…

天体物理学 · 物理学 2007-05-23 O. Bertolami , P. T. Silva

In the current study, we have reconstructed variable modified Chaplygin gas in the Barrow holographic dark energy framework motivated by many recent studies. We have validated the generalized second law of thermodynamics for the…

广义相对论与量子宇宙学 · 物理学 2025-12-02 Sanjeeda Sultana , Chayan Ranjit , Surajit Chattopadhyay

Although various cosmological observations congruously suggest that our universe is dominated by two dark components, the cold dark matter without pressure and the dark energy with negative pressure, the nature and origin of these…

天体物理学 · 物理学 2009-11-10 Zong-Hong Zhu

VLBI observations of supernovae and gamma-ray bursts provide almost the only way of obtaining spatially resolved information about the sources. In particular, a determination of the expansion velocity of the forward shock, as well as the…

高能天体物理现象 · 物理学 2015-06-17 Michael F. Bietenholz

The generalized Chaplygin gas model (GCGM) contains 5 free parameters, here, they are constrained through the type Ia supernovae data, i.e., the ``gold sample'' of 157 supernovae data. Negative and large positive values for $\alpha$ are…

天体物理学 · 物理学 2009-12-30 R. Colistete , J. C. Fabris

It has been widely shown that the cosmological parameters and dark energy can be constrained by using data from type-Ia supernovae (SNe Ia), the cosmic microwave background (CMB) anisotropy, the baryon acoustic oscillation (BAO) peak from…

天体物理学 · 物理学 2009-06-23 F. Y. Wang , Z. G. Dai , Zong-Hong Zhu

We establish new constraints on $f(T)$ gravity models by using cosmological data. In particular, we investigate the restrictions given by the gas mass fraction measurements of galaxy clusters and transversal BAO data. Both data sets are…

宇宙学与河外天体物理 · 物理学 2022-09-28 F. B. M. dos Santos , J. E. Gonzalez , R. Silva

We study a generalized version of Chaplygin gas as unified model of dark matter and dark energy. Using realistic theoretical models and the currently available observational data from the age of the universe, the expansion history based on…

宇宙学与河外天体物理 · 物理学 2010-04-15 Chan-Gyung Park , Jai-chan Hwang , Jaehong Park , Hyerim Noh

Viscous GCG(generalized Chaplygin gas) cosmology is discussed, assuming that there is bulk viscosity in the barotropic fluid and GCG. The dynamical analysis indicates that the phase…

天体物理学 · 物理学 2009-11-11 Xiang-hua Zhai , You-dong Xu , Xin-zhou Li

We use higher-redshift gamma-ray burst (GRB), HII starburst galaxy (HIIG), and quasar angular size (QSO-AS) measurements to constrain six spatially flat and non-flat cosmological models. These three sets of cosmological constraints are…

宇宙学与河外天体物理 · 物理学 2021-01-15 Shulei Cao , Joseph Ryan , Narayan Khadka , Bharat Ratra

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…

广义相对论与量子宇宙学 · 物理学 2024-12-31 Albert Munyeshyaka , Praveen Kumar Dhankar , Joseph Ntahompagaze

In this paper, we revisit generalized Chaplygin gas (GCG) model as a unified dark matter and dark energy model. The energy density of GCG model is given as $\rho_{GCG}/\rho_{GCG0}=[B_{s}+(1-B_{s})a^{-3(1+\alpha)}]^{1/(1+\alpha)}$, where…

宇宙学与河外天体物理 · 物理学 2015-06-04 Lixin Xu , Jianbo Lu , Yuting Wang

We use lookback time versus redshift data from galaxy clusters (Capozziello et al., 2004) and passively evolving galaxies (Simon et al., 2005), and apply a bayesian prior on the total age of the Universe based on WMAP measurements, to…

宇宙学与河外天体物理 · 物理学 2014-11-20 Lado Samushia , Abha Dev , Deepak Jain , Bharat Ratra

The generalized Chaplygin gas (GCG) model explains the recent accelerated expansion of the Universe via an exotic background fluid whose equation of state is given by p=-A/\rho^\alpha, where A is a positive constant and 0<\alpha\le 1. The…

天体物理学 · 物理学 2015-06-24 M. C. Bento , O. Bertolami , A. A. Sen

Baryon acoustic oscillation (BAO) is one of the important standard rulers in cosmology. The results of the latest BAO measurements by Dark Energy Spectroscopic Instrument (DESI) survey have been reported. Cosmology with the varying electron…

宇宙学与河外天体物理 · 物理学 2024-10-23 Osamu Seto , Yo Toda

We consider a very simple toy model for a spatially varying `cosmological constant', where we are inside a spherical bubble (with a given set of cosmological parameters) that is surrounded by a larger region where these parameters are…

天体物理学 · 物理学 2009-11-06 P. P. Avelino , J. P. M. de Carvalho , C. J. A. P. Martins

In this paper, we study two different models of dark energy based on Chaplygin gas equation of state. The first model is the variable modified Chaplygin gas while the second one is the extended Chaplygin gas. Both models are considered in…

广义相对论与量子宇宙学 · 物理学 2015-02-10 E. O. Kahya , M. Khurshudyan , B. Pourhassan , R. Myrzakulov , A. Pasqua

We use the new gamma-ray bursts (GRBs) data, combined with the baryon acoustic oscillation(BAO) observation from the spectroscopic Sloan Digital Sky Survey (SDSS) data release, the newly obtained $A$ parameter at $z=0.6$ from the WiggleZ…

宇宙学与河外天体物理 · 物理学 2012-12-27 Yu Pan , Shuo Cao , Yungui Gong , Kai Liao , Zong-Hong Zhu