Effect of low anisotropy and supernova constraints on cosmological models

Abstract

The 194 supernova Ia data and the effect of anisotropy are combined to reconstruct the dark energy equation of state parameter [Formula: see text] and the deceleration parameter [Formula: see text]. Using the supernovae type Ia data, we evaluate the anisotropy effects (although low) on dark energy parametrization [Formula: see text] and we compare the results with [Formula: see text]CDM model. Present supernova observations are analyzed using a standard [Formula: see text] method and the minimal [Formula: see text] values obtained for each model are compared. We confirm the difficulty of discriminating between these models using present SNIa data only. By means of the maximum likelihood method, we find that the best-fit dynamical [Formula: see text] and [Formula: see text] parameters [Formula: see text] are obtained from the SNIa dataset. In particular, we find the best-fit values of [Formula: see text]CDM model ([Formula: see text] = 0.013, [Formula: see text] = 197.559) for [Formula: see text] = 0.3 and ([Formula: see text] = 0.02, [Formula: see text] = 196.983) for [Formula: see text] = 0.27. Finally, we found that the presence of anisotropy is confirmed in mentioned models via SNIa dataset.