Left-hand panel: fits to our spectroscopic light curves combining quadratically limb-darkened analytic transit light curves with a GP. The black data points show the transit light curve for each wavelength bin, with the central wavelength of each bin given on the right-hand y-axis, and are offset in y for clarity. The green line shows the best-fitting systematics (GP) model, and the red line shows the best-fitting systematics + analytic transit light-curve model. Right-hand panel: the residuals for each fit shown in the left-hand panel, with the rms of the residuals given on the right-hand y-axis. Note: the error bars are smaller than the data points.