Current constraints on dark energy models with the Mukhanov (2013) dark energy equation of state, assuming a uniform prior on w₀. Left-hand side panels: constraints from the combination of astrophysical and cosmological constraints; right-hand side panels: local constraints from Oklo, atomic clocks, and MICROSCOPE have also been used. In all cases the black contours denote the one-, two-, and three-sigma confidence levels, and the colour map depicts the reduced chi-square of the fit for each set of model parameters (the dark red colour corresponds to a reduced chi-square of 1.5 or higher).