Same as Fig. 2 (individual error bars are omitted for clarity). Left panel: the red line shows the locus of an MBB with β = 1.6 for different temperatures (red dots along the line give the values at T_d = 15, 20, 25, 30, 35, and 40 K, from left to right). The purple and orange lines show the loci of dust heated by the LISRF scaled by a factor U for the THEMIS and DL07 grain models, respectively (dots along the lines are for U = 0.1, 0.5, 1, 2, 5, 10, and 20, from left to right). Right panel: the THEMIS dust model (solid purple line) is repeated together with the CMM model from Köhler et al. (2015) for 0.1 <  U <  0.5 (dashed purple line). Purple dots are the emissivity values estimated from the CIGALE-THEMIS best-fit SEDs of each galaxy (see text for details).