Excitation temperature of the CO (6–5) line versus the bolometric luminosity of the TOP100 clumps (left panels) and the luminosity-to-mass ratio (right panels). The excitation temperature was derived using the peak of the Gaussian fit of the CO profiles. The median values for each class are shown as open diamonds and their error bars correspond to the median absolute deviation of the data from their median value. The black solid line is the best fit, the light grey shaded area indicates the 68% uncertainty, and the dashed lines show the intrinsic scatter (ϵ) of the relation. The best fit to the data is indicated by the filled black line.