The marginalized posterior distribution in the Ω_m-ω_DE plane for the ΛCDM parameter set extended by including the redshift-independent value of ωDE as an additional parameter. The dashed lines show the 68 and 95 per cent contours obtained using CMB information alone. The solid contours correspond to the results obtained from the combination of CMB data plus the shape of the CMASS ξ (s). The dot-dashed lines indicate the results obtained from the full data set combination (CMB+CMASS+SN+BAO). The dotted line corresponds to the ΛCDM model, where ω_DE =-1.