Spatial distribution of the particles of the satellite in the x-y and z-y planes at t = 4, 8 and 12 Gyr for the S1 simulation. Green star: initial position of the satellite’s centre. Dotted lines: trajectory of the satellite’s centre. Blue dot: centre of the MW model. Green circle: 10 kpc radius circumference centred in the satellite’s centre at the time of the snapshot. Here the particles represent the total (stars plus DM) mass distribution.