a Parametrized Variable Dark Energy Model:. Structure Formation and Observational Constraints

摘要: In this paper we investigate a simple parametrization scheme of the quintessence model given by Wetterich [Phys. Lett. B594, 17 (2004)]. The crucial parameter is bending b, which related to amount dark energy in early universe. Using linear perturbation and spherical infall approximations, evolution matter density perturbations variable model, obtain an analytical expression for growth index f. We show that increasing b leads less contrast δ, also decreases index. Giving fitting formula at present time, verify approximation relation holds model. To compare predictions with observations, use Supernovae type Ia (SNIa) Gold Sample parameters large scale structure determined 2-degree Field Galaxy Redshift Survey (2dFGRS). best fit values marginalizing on remained ones, are , 1σ confidence level. As final test calculate age universe different choices free it old stars some high redshift objects. Then consistent observation star can solve "age crisis" problem.