Fitted transit light curves for 600B data, showing GP predictive mean in red as well as 1σ and 2σ uncertainty in mean shaded in grey. Left: Fitting the raw light curves. Middle: The same fit minus the best-fit transit model, displaying just the GP fit to the systematics. Right: The same fit minus both the best-fit transit model and the GP mean (fitting the systematics) subtracted, showing the residual white noise.