Top: phase-folded plot of the best transit model of planet b (left) and c (right), over the SC data. In black the model, in red the data binned every hundredth of orbital phase. Center: the same for the radial velocities. Bottom: the TTVs of planet b folded at the orbital period of planet c (left) and those of planet c folded at the first peak of its Lomb-Scargle periodogram (right, Sect. 5.1). For each plot, the lower panel shows the residuals as observed minus calculated (O−C) points.