Band-integrated white light curve of HAT-P-55 observed with GTC/OSIRIS. First row: flux time series of HAT-P-55 and its reference star. Second row: raw light curve after dividing the flux of HAT-P-55 by that of the reference. The red line represents the best-fit combined transit and systematics model. Third row: light curve after removal of the systematics. Fourth row: Best-fit light curve residuals.