Upper panel: map of the CCF_loc series, as a function of orbital phase (in abscissa) and radial velocity in the stellar rest frame (in ordinate). Colors indicate flux values. The vertical and horizontal dashed black lines indicate the mid-transit time and stellar rest velocity, respectively. The four vertical dotted black lines show the times of the contacts. The in-transit CCF_loc correspond to the average stellar line profiles from the regions occulted by WASP-8b across the stellar disk. Middle panel: RVs of the stellar surface regions occulted by the planet (blue points). The green curve is the RV model obtained for the obliquity and rotational velocity in Queloz et al. (2010). The red curve corresponds to our best fit for the solid-body rotation case. Lower panel: residuals between the measured surface RV and our best-fit shown in the middle panel.