Example of calculation of infall time for Auriga simulations. Blue points and dash lines indicate the distance of subhalos 1 (top panel) and 1749 (bottom) from Auriga MW-like Level 3 resolution Halo 27 to the main host galaxy center. Red points and lines indicate the evolution of the virial radius (R_200m) of the main host galaxy at different epochs using the linear relation in Fig B.1. Vertical red dashed lines indicate the last infall time of the subhalo.