Nuclear diagnostic diagrams for the whole HRS sample limited to emission-line objects with S∕N > 3. In the left BPT diagram panel, the broken separation line between AGNs (red) and TRAN (pink) galaxies is from Kewley et al. (2001), while the dotted separation line between TRAN (pink) and HII region-like nuclei (blue) is from K03. In the second BPT diagram panel, the extreme starburst classification line is from Kewley et al. (2001), while the separation between LINER (pink) and SEY (red) is from Kewley et al. (2006). We note that the pink filled symbols refer to different types of objects in the three diagrams. The third panel reports the BPT diagram for the minority of galaxies (101) with [OI] in emission. In the WHAN diagram the separations between the different classes are from Gavazzi et al. (2011).