Generalized equation of state for dark energy

Abstract

A generalized parametrization ${w}_{\ensuremath{\beta}}(z)$ for the dark energy equation of state is proposed and some of its cosmological consequences are investigated. We show that in the limit of the characteristic dimensionless parameter $\ensuremath{\beta}\ensuremath{\rightarrow}+1$, 0 and $\ensuremath{-}1$ some well-known equation of state parametrizations are fully recovered whereas for other values of $\ensuremath{\beta}$ the proposed parametrization admits a wider and new range of cosmological solutions. We also discuss possible constraints on the ${w}_{\ensuremath{\beta}}(z)$ parameters from current observational data.