Left panel: distribution of a_IR coefficients as a function of the galaxies g−r SDSS color for the Hα+22 μm hybrid tracer. Orange points show type-2 AGN galaxies while blue points represent star-forming galaxies. Filled contours represent the 1σ dispersion after applying a 5σ rejection around the mean value expressed as a blue (orange) solid line for the SF (type-2 AGN) galaxies. The corresponding histogram with the distribution of the number of galaxies for each g−r SDSS color is plotted on the top for reference applying the same color-coding. Right panel: same as the left panel, except showing the Hα+TIR hybrid tracer. There is a clear offset between the star-forming and type-2 AGN host galaxies with the a_IR coefficient at any g−r SDSS color.