J. S. Alcaniz

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

Some observational consequences of brane world cosmologies

, where

Cosmological constraints on Chaplygin gas dark energy from galaxy cluster x-ray and supernova data

A

Brane world cosmologies and statistical properties of gravitational lenses

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

Current and future supernova constraints on decaying Λ cosmologies

CDM scenarios.

The angular size–redshift relation in power-law cosmologies

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

Deflationary cosmology: Constraints from angular size and ages of globular clusters

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

Constraining the dark energy with galaxy cluster x-ray data

(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.