Acceleration of the universe: a reconstruction of the effective equation of state
The present work is based upon a parametric reconstruction of the effective or total equation of state in a model for the universe with accelerated expansion. The constraints on the model parameters are obtained by maximum likelihood analysis using the supernova distance modulus data, observational Hubble data, baryon acoustic oscillation data and cosmic microwave background shift parameter data. For statistical comparison, the same analysis has also been carried out for the wCDM dark energy model. Different model selection criteria (Akaike information criterion (AIC) and (Bayesian Information Criterion (BIC) give the clear indication that the reconstructed model is well consistent with the wCDM model. Then both the models (w_{eff}(z) model and wCDM model) have also been presented through (q_0 ,j_0 parameter space. Tighter constraint on the present values of dark energy equation of state parameter (w_{DE}(z 0) and cosmological jerk (j_0) have been achieved for the reconstructed model.