Luminosity peak time of the corresponding radio light curves in each cluster mass bin versus mass of the main cluster progenitor. The solid line corresponds to the best-fit t_peak = (0.39 × log(M_200,1/10¹⁴ M_⊙) + 0.49) Gyr. Bars show the FWHM emission time, providing a measure of relic duration for each cluster mass bin. Dash-dotted and dotted lines correspond to the additional best-fitting cases shown in Fig. 9.