Distributions of characteristic timescales (t_δ) of the periodicity of the flickering δ. Each line is a PDF that is computed by weighting for the peak significance (w) for a sub-sample of galaxies falling in a different mass by z = 7.7. For increasing mass bins, the sub-samples contain 35, 89, 100, and 11 galaxies (typically, about four peaks per galaxy are found). The PDF was computed via a kernel density estimator, adopting the rule of thumb of Silverman (1986) for the size of the bandwidth.