BPT diagnostic diagram (Kewley et al. 2006) with topological classification based on Kauffmann et al. (2003), Kewley et al. (2001), and Schawinski et al. (2007). We show the two components of the double-peak galaxies: 58 triangles represent the strong [OIII] component and 33 circles the weaker [OIII] component. We display the 25 upper limits with an arrow for those galaxies, which have a suppressed component with S/N <  3. We highlight galaxies with an off-centred weak [OIII] line with an empty marker (see Sect. 2.3).