Joint RV-data plot of two different transit events of HAT-P-17 b, fitted with two different models: RV only (left-handpanels) and RM+CB (right-hand panels). Left-hand panels: grey squares are the HIRES RVs (Fulton et al. 2013). Note that the two circled data points were considered outliers (they showed residuals larger than 4σ and, therefore, were not considered in the modelling process). Black points are the HARPS-N RVs (this work). The best-fitting values of the systemic RVs were subtracted in order to compare the two data sets. The red line represents the best-fitting model of the RM effect; the RV residuals are plotted in the lower panel. Right-hand panels: same as left panels but with the RM effect and CB effect modelled simultaneously (green-dashed line).