Fitting of the [O I] doublet and Hα profiles. Dashed blue lines indicate the rest wavelength for 6300 Å and 6564 Å in the left and right panels, respectively, and the dashed gray line indicates the rest wavelength for 6456 Å, which could be associated with O I or Fe II. The thin lines show the individual Gaussian components. See Sect. 3.2 for the interpretation of the line components.