BPT diagnostic diagram for the Sy2 sample. The various levels of obscuration are color-coded. The continuous curve denotes the star-forming − AGN separation line of Kauffmann et al. (2003), and the thick dashed curve the respective line of Kewley et al. (2001). The dashed straight line denotes the LINER − AGN threshold by Schawinski et al. (2007). Composite or transition objects (TO) between the AGN and star-forming phase are found in the area between the two curves. The open square indicates the position of a discarded LINER.