Diagrams showing the loci of our radio Seyfert (green), OPARG (blue), and OPIRG (red) subsamples in relation to our parent samples: ROGUE I & II SDSS MGS (‘ROGUE-MGS’) for panel (a), SDSS MGS (‘MGS’) for panels (b) and (c) (grey points). (a) D_n(4000) versus L_1.4/M_★ (DLM) plane. The dashed line by Kozieł-Wierzbowska et al. (2021) separates radio emission dominated (top) or not (bottom) by AGN. (b) [O III]λ5007/Hβ versus [N II]λ6584/Hα (BPT) plane. The dashed line by Stasińska et al. (2006) separates galaxies ionized by star formation alone (left) from those ionized by a hard ionizing radiation field (right). OPIRGs are not shown since they have not been selected based on this diagram. (c) W(Hα) versus [N II]λ6584/Hα (WHAN) plane. The dashed line shows the W(Hα) = 3 Å criterion by Cid Fernandes et al. (2011) to separate ionization by HOLMES (bottom) from ionization by other sources (top). OPIRGs that lack [N II] detection are not shown on this plane.