Upper panel: phase folded radial velocity measurements of WASP-54 obtained combining data from SOPHIE (filled-circles) and CORALIE (open-squares) spectrographs. Superimposed is the best-fit model RV curve with parameters from Table 4. The centre-of-mass velocity for each data set was subtracted from the RVs (γ_SOPHIE = −3.1109 km s^-1 and γ_CORALIE = −3.1335 km s^-1). Lower panel: residuals from the RV orbital fit plotted against time.