Bayesian probability distributions of the H₂O parameters for the fit to the reference spectrum. The abscissa scale in the N_H2O and T panels is different here from that in Fig. 3. For the Bayesian analysis, we varied T in steps of 2.5 K, N_H2O in logarithmic steps of 0.025, R_e in steps of 0.1 AU, and P in steps of 0.05. The step widths for T and N_H2O are smaller than those used in Fig. 3 (see Sect. 3.1). These plots show that the strong peaks are not due to an insufficient sampling of the parameters.