Comparison of RV and B_l data sets obtained with a parametric selection of sub-masks. Top: RV (left) and B_l (right) data sets obtained with a depth selection. Middle: same, but with a wavelength selection. Bottom: same, but with a Landé factor selection. In all panels the black data points correspond to either the RV or the B_l values obtained with the full mask, whereas the continuous lines represent the sinusoidal fit of the associated data set. The mean of the data set is subtracted to allow a simpler comparison. For RV estimates, the error bars are set to 30 m s⁻¹, as derived from the telluric line-based wavelength calibration of the spectra (Moutou et al. 2007), which is greater than the photon noise for each of these data sets. For B_l the formal uncertainties are used. The displayed data sets are 3σ clipped to prevent outliers from affecting the results. For B_l the densest epoch (2010) is displayed.