Two RV time-series and their difference. Top: comparison between the RVs derived from the Gaussian fit and the EPiCA method. The data (RV changes in m s⁻¹) are plotted as a function of exposure number. The pipeline RVs are plotted with their error bars, in a different color for each night. They were derived by subtracting from all pipeline RV data contained in each spectrum fits file the value of the first exposure: 31.3668 km s⁻¹. Red points are obtained by the EPiCA method applied to the CCFs of the current exposure and the first exposure of night 24 (exposure n°10 when all nights are concatenated), taken as a reference. A constant 2 m s⁻¹ was subtracted for clarity. Bottom: differences between the two time series of RV changes: Gaussian fit – EPiCA (CF1 applied to CCF_tot). This difference shows an abrupt decrease (~1.3 ms⁻¹) after exposure no. 615, corresponding to the transition from night 25 to night 26, which remains after that.