I13120 velocity diagram and maps. Left panel: I13120 velocity shift ΔV_j − FWHM_j diagram (coloured by density in log-scale) for the individual Gaussian components used to model the emission line profiles in the data cube. The dashed red lines isolate the Gaussian components used to reconstruct the narrow Hα data cube, with |ΔV_j|< 250 km s⁻¹ and FWHM_j < 400 km s⁻¹. Right panels: narrow Hα flux distribution, velocity (v50), and line width (W80) maps, reported in the second, third, and fourth panels, respectively (see Fig. 2 for details).