GJ 1148 Doppler data obtained with HIRES (green diamonds) and CARMENES (red circles) show two distinct periodic signals consistent with two eccentric Saturn mass planets with orbital periods of 41 d and 526 d. Panels a and b show the GLS signal of the dominant planet GJ 1148 b and its single planet Keplerian model phase folded at the best-fit period, respectively. Panels c–e show the GLS analysis of the HIRES, CARMENES and the combined data residuals after subtracting the signal from GJ 1148 b shown in panel b. Both data sets reveal the existence of a second planet candidate with a period near 530 d. Panel f: shows the RV signal of the second planet as determined from the simultaneous two-planet fit, while panels g and h show the individual Doppler signals of GJ 1148 b and GJ 1148 c, respectively, phase folded at their best-fit periods.