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.
