PSD of the Sector 27 data of the red giant TIC 374859063, computed up to the Nyquist frequency. The input light curve was processed following the procedure described in Sect. 3. The blue portion of the PSD was used in the subsequent analysis, where a piecewise linear fit in the log-log space was applied (black line). The gray part of the PSD is influenced by the SG filtering and is therefore excluded.