Colour-coded map: projected mass density of gas in the simulated satellite galaxy at t = 100 Myr after the first pericentre passage. Both the satellite and the S0 galaxy are seen edge-on. The scale of the colour-coded map is logarithmic, ranging from 2.2 × 10^-9 M_⊙ pc^-3 (black) to 7.0 × 10^-2 M_⊙ pc^-3 (white). The frame size is 16 × 16 kpc. The red circle marks the position of the nucleus of the satellite galaxy. The yellow contours show the projected density of stars in the S0 galaxy.