Colour-coded map: projected mass density of gas in the simulated satellite galaxy at t = 100 Myr after the first pericentre passage. The satellite is seen face-on. The scale of the colour-coded map is logarithmic, ranging from 2.2 × 10^-9 M_⊙ pc^-3 (black) to 2.2 × 10^-2 M_⊙ pc^-3 (white). The frame size is 60 × 60 kpc. The red circle marks the position of the nucleus of the satellite galaxy. The direction of the S0 bulge is indicated by the red arrow.