Fit of the Hβ + [O III] (left) and Hα + [N II] lines (right), after the continuum and iron subtraction. We modeled the BLR Hβ and Hα lines using two Lorentzian functions (one for each line). The nebular lines from the NLR ([O III], [N II], Hα, and Hβ narrow components) were each fitted with a Gaussian. We added two further Gaussian components (purple; “broad” components in the paper) to fit the emission around 5000 Å, likely associated with blueshifted [O III] (see also Sect. 4.4 and Fig. 8). The residuals are shown in orange.