Related papers: Observational Constraints on Variable Chaplygin Ga…
The properties of nearby galaxy clusters limit the range of cosmological parameters consistent with our universe. We describe the limits which arise from studies of the intracluster medium (ICM) mass fraction fICM and consideration of the…
We examine the constraints that can be obtained on standard cold dark matter models from the most currently used data set: CMB anisotropies, type Ia supernovae and the SDSS luminous red galaxies. We also examine how these constraints are…
In this paper, viscous generalized Chaplygin gas as a model of dark energy considered. We assume non-constant bulk viscous coefficient and study dark energy density. We consider several cases of density-dependent viscosities. We find that,…
We will extend the study of the new generalized Chaplygin gas (NGCG) based on [JCAP 0601(2006)003]. Concretely, we will not only discuss the change rates of the energy densities and the energy transfer of this model, but also perform the…
The type Ia supernovae observational data is one of the most important in observational cosmology nowadays. Here we present the first public version of BETOCS (BayEsian Tools for Observational Cosmology using SNe Ia), which is a powerful…
Recent analysis of the combined data of cosmic microwave background, galaxy clustering and supernovae type Ia observations have set strong constraints on the equation of state parameter $w_X$. The upper bound $w_X < -0.82$ at 95% c.l. rules…
In this paper, we continue our previous work of studying viscous generalized Chaplygin gas (VGCG) as a unified dark fluid but including the bulk viscosity perturbation. By using the currently available cosmic observational data from SNLS3,…
In this paper, we attempt to explore the possibility of a obtaining a viable emergent universe scenario supported by a type of fluid known as the extended Chaplygin gas, which extends a modification to the equation of state of the well…
We use Hubble parameter versus redshift data from Stern, et al(2010) and Gazta\~{n}aga, et al (2009) to place constraints on model parameters of constant and time-evolving dark energy cosmological models. These constraints are consistent…
We examine the constraints that satellite-acquired Type Ia and IIP supernova apparent magnitude versus redshift data will place on cosmological model parameters in models with and without a constant or time-variable cosmological constant…
We constrain two non-flat time-evolving dark energy cosmological models by using Hubble parameter data, Type Ia supernova apparent magnitude measurements, and baryonic acoustic oscillation peak length scale observations. The inclusion of…
This paper explores the thermodynamic properties and stability of two newly introduced gas models, namely the Modified Chaplygin-Jacobi gas and the Modified Chaplygin-Abel gas. To achieve this, we examine the behavior of relevant physical…
We use the Allen et al. (2004) Chandra measurements of x-ray gas mass fraction of 26 rich clusters to place constraints on the scalar-field dark energy model with inverse power law potential energy density. The constraints are consistent…
We study the implications on both background and perturbation evolution of introducing a Chaplygin gas component in the universe's ingredients. We perform likelihood analyses using wide-ranging, SN1a, CMB and large scale structure…
The universal baryonic mass fraction (Omega_b/Omega_m) can be sensitively constrained using X-ray observations of galaxy clusters. In this paper, we compare the baryonic mass fraction inferred from measurements of the cosmic microwave…
We discuss the issue of toy model building for the dark energy component of the universe. Specifically, we consider two generic toy models recently proposed as alternatives to quintessence models, known as Cardassian expansion and the…
Recently it was found that dark energy in the form of phantom generalized Chaplygin gas may lead to a new form of the cosmic doomsday, the big freeze singularity. Like the big rip singularity, the big freeze singularity would also take…
We review the difficulties of the generalized Chaplygin gas model to fit observational data, due to the tension between background and perturbative tests. We argue that such issues may be circumvented by means of a self-interacting scalar…
Significant adjustments to the values of the cosmological parameters estimated from high-redshift Type Ia Supernov\ae data are reported, almost an order of magnitude greater than previously found. They arise from the effects of weak…
Recent measurements of type Ia supernovae as well as other concordant observations suggest that the expansion of our universe is accelerating. A dark energy component has usually been invoked as the most feasible mechanism for the…