Intensity-weighted stacking. Top: radial stacking similar to Fig. 2, but using the intensity of the prior, i.e. the “S/N/1” integrated intensities, as a weight following Eq. (4). The black solid line shows the template, i.e. the true, radial profile, where the template line intensities are used as the weight. The black dashed line shows the non-weighted radial trend of the template stacking also shown in Fig. 2. Bottom: deviation, in per cent, of the stacked radial trend from the template profile. The hatched area denotes the regime, where the prior, i.e. S/N/1, is detected in less than 20% of the pixels.