Abha Dev

Cosmological consequences of a Chaplygin gas dark energy

A combination of recent observational results has given rise to what is currently known as the dark energy problem. Although several possible candidates have been extensively discussed in the literature to date the nature of this dark energy component is not well understood at present. In this paper we investigate some cosmological implications of another dark energy candidate: an exotic fluid known as the Chaplygin gas, which is characterized by an equation of state

High-redshift objects and the generalized Chaplygin gas

p = -A/\rho

Constraints on Chaplygin quartessence from the CLASS gravitational lens statistics and supernova data

, where

Brane world cosmologies and statistical properties of gravitational lenses

A

Cosmological tests for a linear coasting cosmology

is a positive constant. By assuming a flat scenario driven by non-relativistic matter plus a Chaplygin gas dark energy we study the influence of such a component on the statistical properties of gravitational lenses. A comparison between the predicted age of the universe and the latest age estimates of globular clusters is also included and the results briefly discussed. In general, we find that the behavior of this class of models may be interpreted as an intermediary case between the standard and

Age constraints on brane models of dark energy

\Lambda

The angular size–redshift relation in power-law cosmologies

CDM scenarios.

Linear coasting in cosmology and SNe Ia

Motivated by recent developments in particle physics and cosmology, there has been growing interest in a unified description of dark matter and dark energy scenarios. In this paper we explore observational constraints from age estimates of high-z objects on cosmological models dominated by an exotic fluid with an equation of state

CONSTRAINTS ON THE CARDASSIAN EXPANSION FROM THE COSMIC LENS ALL-SKY SURVEY GRAVITATIONAL LENS STATISTICS

p=\ensuremath{-}A/{\ensuremath{\rho}}^{\ensuremath{\alpha}}

DARK ENERGY AND THE STATISTICAL STUDY OF THE OBSERVED IMAGE SEPARATIONS OF THE MULTIPLY-IMAGED SYSTEMS IN THE CLASS STATISTICAL SAMPLE

(the so-called generalized Chaplygin gas) which has the interesting feature of interpolating between nonrelativistic matter and negative-pressure dark energy regimes. As a general result we find that, if the age estimates of these objects are correct, they impose very restrictive limits on some of these scenarios.