Upper left panel: the CO SLED (without correcting for lensing magnification) of each source is plotted in black. The flux of CO(1–0) has been corrected for differential lensing effect as discussed in the text. The solid orange curve shows the best fit from the single component model corresponding to the maximum posterior possibility, while the solid purple line shows the best fit of the two-component model. Dashed red line shows the warmer component and the dashed-dotted line shows the cooler component fit. The upper limits are shown in grey open circles with downward arrows. Upper right panel: the posterior probability distributions of molecular gas density n_H2, gas temperature T_kin and CO column density per velocity N_CO/ dv of the source, with the maximum posterior possibility point in the parameter space shown in orange lines and points. The contours are in steps of 0.5 σ starting from the centre. Lower panels: the posterior probability distributions for n_H2, T_kin and N_CO/ dv of the cooler (dark green) and warmer (light green) component of the two-component model.