Number of significant progenitors as a function of each galaxies’ accreted mass, colour-coded by their stellar halo mass. We do not find any clear correlation between these quantities. The open circle represents Auriga 15 with M_acc = 9.74 × 10⁴ M_⊙, which means that it has a low amount of accreted particles due to the simulation’s resolution and hence the number of these particles is insufficient for a robust result.