Comparison between a model using a combination of three WAs and dust as opposed to WAs alone. Upper panel: Model implementing three WAs and dust (red) vs. WAs alone (blue). The latter case does not take into account the additional absorption in the 15 − 18 Å region, while the WAs and dust model does. The RGS data are shown in black. Middle panel: Residuals of the WA and dust model. Lower panel: Residuals of the WA model.