Evolution of model A (M_⋆ = 1.4 × 10⁸ M_⊙) with R_g = 2R_d merging with a 20% mass satellite on a co-planar, very radial orbit. The top rows show the face-on and edge-on, respectively, view of the gas in the disk (contours at 0.25, 1, 4, and 16 × 10²⁰ N cm^-2) with the gas that is currently forming stars highlighted in green (see colorbar for relative values). The bottom panels show the old stellar component in red, and newly formed star particles in black, at different times during the merger.