Same as Fig. 6 but showing the Allen et al. (2008) grids of shock-ionisation models. These grids have been generated assuming a shock+precursor model with twice solar metallicity and pre-shock density of n_e = 1000 cm^-3. Gridlines corresponding to 3 values of magnetic field (B = 1, 10 and 100 μG) and 9 shock velocity values (v_s = 200, 300, 400, 500, 600, 700, 800, 900 and 1000 km s^-1) are shown in the figure. v_s increases always from bottom to top with 3 values (200, 400 and 1000 km s^-1) indicated in the figure. As in the case of Fig. 6, the gridlines these are grey-coded from “light-grey” to black, with light-grey and black corresponding to the lowest and highest values of B and v_s respectively. The symbols and colors are the same as in Fig. 6. (A color version of this figure is available in the online journal.)