Dark energy equation of state parameter and its evolution at low redshift

Abstract

In this paper, we constrain dark energy models using a compendium of\nobservations at low redshifts. We consider the dark energy as a barotropic\nfluid, with the equation of state a constant as well the case where dark energy\nequation of state is a function of time. The observations considered here are\nSupernova Type Ia data, Baryonic Acoustic Oscillation data and Hubble parameter\nmeasurements. We compare constraints obtained from these data and also do a\ncombined analysis. The combined observational constraints put strong limits on\nvariation of dark energy energy density with redshift. For varying dark energy\nmodels, the range of parameters preferred by the supernova type Ia data is in\ntension with the other low redshift distance measurements.\n