8−1000 μm IR luminosity L_IR (left panel) and the CO (1−0) luminosity L_CO (right panel) plotted against Hα luminosity. The training sample from the xCG (gray dots) is compared to the CARS objects (red circles and triangles for the 5σ upper limits). Galaxy mergers in the xCG sample as classified by GalaxyZoo2 are additionally marked (black crosses) on the left panel. The blue dashed line corresponds to Eqs. (12) and (13) are derived by the combination of literature calibrations as described in the main text. The black lines represent a linear relation fitted to the XCOLD GASS reference sample, see Eqs. (14) and (15). The red dotted line is fitted to the CARS objects with the same slope as the black line, therefore highlight the shift in the normalization.