Examples of one (top) and two (bottom) component(s) Gaussian fits to the NaD line profiles in two different spaxels in IRAS F10409-4556. Below, the residuals (i.e., data – model) are presented. When fitting two components the blueshifted component is shown in blue (bottom panel only). The red curve shows the total contribution coming from the NaD Gaussian fit. In bracket, the spaxels coordinates indicated as distance from the nucleus (i.e., map center, Fig. A.23).