Multi-component fit for diffuse gas emission lines of MR 2251−178 (top panels) and PG 1126−041 (bottom panels). Left-hand panels: iso-intensity contours for the integrated [O III] line (black lines); the background colours show the number of components used in each Voronoi bin. The [O III] maps are derived by integrating the (unbinned) BLR-subtracted cubes in the λλ4930−5030 Å rest-frame range and are spatially smoothed to a FWHM resolution of 0.25″. Contours are spaced by a factor of 2, the outermost being at 3× the rms noise. The crosses in cyan mark the bins at which the spectra shown in the right panels are extracted. Right-hand panels: representative spectra in a range encompassing the Hβ and [O III] lines for the BLR-subtracted cubes (black lines), our best-fit models (blue lines), and their HV sub-components alone (orange lines).