Summary of the GP analysis of the optical RV time series using SPIRou's B_ℓ as an activity proxy. Upper left: QP GP fit (green line) to the HARPS and SOPHIE optical RV time series (black points). The median value of the raw RV is denoted by γ. Upper right: periodogram of the RV data and window function before the QP GP fit. The horizontal line is the FAP = 0.1%. Lower left: residuals in the optical RVs after the subtraction of the QP GP fit. Lower right: periodogram of the RV residuals after subtraction of the QP GP fit. In the top of each periodogram, the period, and FAP of the strongest peak are given. Details of the GP model are summarized in Table 6. The corner plot of the fit is given in Fig. B.2.