Left column: radial velocity time series extracted from HARPS-N spectra using the DRS (upper panel) and TERRA (lower panel) pipelines. Right column: GLS periodograms of the RV time series (blue line). Vertical dashed lines mark the location of the highest peak at ~8.5 days and the stellar rotation frequency, for all the datasets. Vertical dotted lines in red mark the orbital frequenciesof the K2-36 planets. For the DRS dataset only, we show the periodogram of the residuals, after subtracting the signal with period of 8.5 days (grey line), with the main peak located at P ~16.5 days, which corresponds to the stellar rotation period. The window function of the data (not shown) is the same as in Fig. 5.