Top: comparison between observed emission profiles for cut 1 (green line) with modelled emission profiles obtained with the best set of parameters (see Table 1) for case a (blue line), case b (orange line), and case c (purple line). Middle: same for cut 2. Bottom: same for cut 3. The grey parts correspond to the inner Horsehead, where AMM and AMMI grains are used in case b and case c, respectively.