White light curve for the simultaneous transits of TOI-270 b and d observed with JWST NIRSpec G395H. The top panel shows the combined white light curve from NRS1 and NRS2, together with the best-fit models of the two transits shown in orange and purple. We mask the overlap region from the model fitting, indicated in grey. In both cases, we fit the transits using the out-of-transit flux on both sides. The bottom panel shows the residuals after subtracting the best-fit models. The standard deviation of the residuals is 100 ppm, corresponding to 1.2 times the expected noise level, similarly to other NIRSpec G395H observations.