Top: visualisation of the method described in Halle et al. (2015) to infer the R_g(t) of the particles: the radial evolution of three random particles in the K9_i simulation with respect to time. R_g(t) (pink) is the mean of R_max(t) (dark brown) and R_min(t) (light brown), and its value at the start of the simulation is R_g(t_i) (horizontal dashed black line). The times of the pericentre passages of G_SMC are shown in vertical dashed grey lines, and the evolution of the galactocentric radius of the particles, R(t), is the dark blue curve. The black vertical line represents the t=0 snapshot that is displayed on the bottom panel. Bottom: visualisation of the method for inferring the guiding radius, R_g(t), of a particle at t=0 (same legend as above, with the previous orbit of the particle in white). The shown particle is the particle with the highest radius from the top panel. G_{S MC} is shown in the lower right hand corner, but its particles are not tracked in this work. An animated visualisation is available online.