Derived bolometric luminosity as a function of the projected distance from the galaxy nucleus, as described in Fig. 9. The model outlined in Sect. 3.5 was run with different values of alpha in the range 13.6–500 eV. This change in the shape of the continuum correspond to the dispersion of values in the He II/Hβ ratio, showing as a solid line the median value, and in dotted lines (shaded in between) the ±1σ difference. For most of the galaxies in the sample, the change in the shape of the continuum translates into a small difference in the luminosity curve. SDSS 1510, which despite showing a larger spread in L_bol, maintains the trend of increasing luminosity with projected distance.