Top panels: pPXF best-fit model results for a type 1.9 AGN (orange curve) superimposed on the rest-frame SDSS spectrum. All the prominent emission lines and analysed features are highlighted with vertical dotted lines; the positions of Mg I b and Na I D absorption lines are also indicated. The inset on the left shows the SDSS colour-composite cut-out of the galaxy with a red square indicating the spatial region from which the 3′′ spectrum was obtained. Bottom panels: fit results from the multicomponent simultaneous fit in the Hβ-[O III] (left) and Hα-[NII] (right) regions. Green and blue curves show the NC and OC Gaussian profiles, while the red lines represent the total best-fit profile. The insets on the right of each panel show the excess in the Balmer emission lines found after the correction for the pPXF best-fit model (the orange curves represent the difference between the SDSS spectrum and pPXF and simultaneous fit models). The original spectrum is also shown for a qualitative evaluation of the contribution of stellar absorption feature in the observed emission line. Magenta Gaussian profiles represent best-fit results associated with significant (>5σ) residuals. The insets on the left of the Hα+[N II] panels show the best-fit models of [O I]λ6300.