Criteria for separating AGN from SFGs, using Spitzer/IRAC bands, updated by Donley et al. (2012). The x-axis represents the ratio of fluxes in the 5.8 μm and 3.6 μm bands, while the y-axis represents the ratio of fluxes in the 8.0 μm and 4.5 μm bands. The area bounded by the black dashed lines corresponds to the selection criterion defined by Donley et al. (2012). The colour-coding represents the spectroscopic redshift of the objects. The average 1σ size is shown in red at the bottom right.