BPT diagrams of PGC 073000. Left to right: [N II]-BPT, [S II]-BPT and [O I]-BPT diagrams. Up to down: BPT diagrams of the first, blueshifted, and redshifted components. The solid curves define the theoretical upper bound for pure star formation (Kewley et al. 2001), the dashed curve in [N II]-BPT defines the upper bound for star formation dominated bins (Kauffmann et al. 2003), and the dashed lines in [S II]-BPT and [O I]-BPT divide Seyfert galaxies from LINERs (Kewley et al. 2006). In the bottom left corner of each diagram the median ±3σ errors are reported. Seyfert-type ionisation is indicated in blue, LI(N)ER regions in the [S II]-BPTs and [O I]-BPTs are displayed in green, SF-dominated bins in red, while composite regions between Kewley et al. (2001) and Kauffmann et al. (2003) curves in [N II]-BPTs are indicated in light blue.