Fit to the nuclear spectrum of HE 1353−1917 in the wavelength regions around Hβ and Hα after continuum subtraction. Upper panels: overlay of the nuclear spectrum (black) and the total fit (red). The residuals from the fit are indicated in gray (offset from the nuclear spectrum for better visibility). Lower panels: individual Gaussian components fitted to the nuclear spectrum together with an Fe II template from Kovačević et al. (2010). All components shown with the same color were kinematically tied to each other during the fit. This includes the narrow components (Hβ_n, [O III] λ4959 and λ5007, [O I] λ6300 and λ6364, [N II] λ6548 and λ6583, and Hα_n and [S II] λλ6717, 6731) shown in blue, the broad components (Hβ_b and Hα_b) shown in yellow, and the very broad components (Hβ_vb and Hα_vb) shown in red.