Blazars with TESS: Validating TESS reduction pipelines applied to blazars using ZTF observations

Blazars are characterized by largely aperiodic variability on timescales ranging from minutes to decades across the electromagnetic spectrum. The TESS mission, with its 30-minute Full Frame Image (FFI) sampling rate for at least 27 consecutive days, provides insight into blazar variability on timescales that have only previously been studied with Kepler/K2 on a much more limited sample of blazars. Proper removal of background and systematic effects is crucial to the subsequent analysis and interpretation of blazar variability on these timescales. A number of publicly available procedures exist that extract light curves from TESS FFIs and claim to properly correct for background and systematic effects. We present the results of a comparison of the light curves extracted using 5 of these methods, utilizing ZTF ground based data as the “ground truth” observations. We find that only two of the five methods compared (Simple Differential Photometry (SDP) and Quaver pipeline) methods produce TESS light curves consistent with the ground-based ZTF observations.