Comparison of numerically (here log temperature in K is colour-coded) and analytically derived results. The thin line represents the outer envelope of the galaxy, whereas the thick line represents the bow shock. Upper left. Model of the interaction between NGC 7318b and the IGM in SQ at the time t = 60   Myr (j = 0, ). Upper right. Same as upper left, but at at t = 130   Myr (j = 0, ). The lower panels give the corresponding percentage errors.