Example of a periodicity analysis of the SFR variability for the same high-mass (upper panel) and low-mass galaxies (lower) as presented in Fig. 1. For each galaxy, we plot the Lomb (1976)–Scargle (1998) periodogram of the variability (P(t_δ)) as a function of the frequency (). Each peak recovered above the selected noise threshold (dotted line) is marked in the plot with a dashed line, and its characteristic time (t_δ) and significance (w) are given. As a reference, we plot in the inset the evolution of δ vs. cosmic time (t) shifted by t₀, that is, the time at which the stellar mass becomes > 10^6.5 M_⊙.