Zoom-in into the D1 region, showing the combined SW observations (F115W+F150W+F200W), the best-fit model of the core region, and its residuals. The apertures used for photometry are shown as white ellipses; for the D1_core region, photometry is derived from a light-profile fitting (as described in the main text). For each of the apertures/regions, photometry is shown as black circles, with the SED best-fit model over-plotted as colored empty squares and relative spectrum. The best-fit of the UV slope is also shown and reported in the panels.