PSD of the residuals for the first pass of Arc 22 for the three noise scenarios: white noise (left), colored noise without whitening (middle), and colored noise with whitening applied (right). For the white noise and whitened colored noise cases, the flat spectra indicate white-noise behavior. Moreover, we verified that the standard deviation of the PSD matches its mean, consistent with Equation (13) of J. Timmer & M. Konig 1995). In contrast, the nonwhitened colored noise exhibits a decaying trend typical of red noise.