Properties of simulated subhaloes at infall. We used the merger trees to track the subhalo evolution and measure their properties at infall, i.e. at the redshift where they first entered their host halo. We plot the normalised distribution of infall redshifts z_infall (left) and the mass at infall M_infall (right). The orange histograms show the distribution of the subhaloes selected as analogues, i.e. those lying within the orange boxes in the top panels of Fig. 8 for which we show the density profiles in the bottom panels of the same figure. The grey histograms show instead the distribution for all subhaloes in the same host haloes and with final masses between 2×10⁸ M_⊙≤M_sub(z = 0.89)≤5×10⁹ M_⊙ for B1938+666 and 10⁹ M_⊙≤M_sub(z = 0.2)≤4×10¹¹ M_⊙ for J0946+1006.