The narrow line-core components

The spectra were deredshifted assuming z = 0.0434 (Fig. a and b) and analysed in terms of Gaussian components as described above. We discovered first that the core of the lines could not be fitted by a single set of narrow Gaussian profiles. To get a satisfactory fit, two sets of Gaussian components are needed: the first, unresolved (and subsequently taken as the origin of the velocity scales) has $\lambda$6583/H$\alpha$ = 0.55 and $\lambda$5007/H$\beta$ = 1.27 and corresponds to a Hii region (Fig. ); the second is resolved (FWHM $\sim$ 350 kms^-1, corrected for the instrumental broadening), blueshifted by $\sim$ 95 kms^-1 with respect to the narrower components and has line intensity ratios typical of a Seyfert 2 ($\lambda$6583/H$\alpha$ = 0.84, $\lambda$5007/H$\beta$ = 10.2).