Baldwin–Phillips–Terlevich diagrams according to the Kewley et al. (2006) classification scheme, produced using SDSS DR7 data. The yellow star indicates the position of UGSC in the diagrams. The error bars are smaller than the symbol size and thus cannot be depicted. The red curve (Ke01) denotes the demarcation between star-forming galaxies and AGN as defined by Kewley et al. (2001). The green curve (Ka03) shows the same demarcation as defined by Kauffmann et al. (2003). SF stands for a star-forming galaxy region.