RM effect fit using the GP+PyAstronomy package on the ESPRESSO RVs taken from the spectrum headers. Top panel: RV curve with Kepler motion and red noise removed, showing the RM effect of WASP-85Ab of the three transits represented by the red, green, and blue circles with error bars. The best-fit model using the PyAstronomy package is shown in the solid line. Bottom panel: residuals between the data and the model predictions.