Current constraints for the n = 1/2 case, using Q_1/2 as free parameter. Top panels: black solid curves show the one, two, and three sigma confidence levels in the two-dimensional plane, while the color map depicts the reduced chi-square; the left panel indicates the case of a fixed H₀, while in the right panel it has been analytically marginalized. Bottom panels: one-dimensional posterior likelihoods for both parameters; the dashed lines correspond to the fixed H₀ and the solid lines to the marginalized case.