MIR diagram where colors are obtained as ratios of the fluxes in the four IRAC channels. Symbols are identical to Fig. 6. The solid lines delineate the region where AGN are typically found according to Lacy et al. (2007), while the dashed lines define the less contaminated AGN region identified in Donley et al. (2012). A blob characterized by a high concentration of stars can be seen in the lower left part of the diagram, while inactive galaxies tend to occupy the roughly vertical, scattered sequence defined by small violet dots.