Results from the first spectropolarimetric survey of $\gamma$ Dor pulsators
Context. Magnetic fields can have an important influence on stellar structure and evolution. In intermediate-mass (A- and F-type) stars, there are many known stars with directly measured strong, globally organized magnetic fields, as well as indications of weak and/or small-scale variable fields. However, among the intermediate-mass $\gamma$ Dor pulsators, there are no known stars with strong surface magnetic fields. Aims. The broad goal of this work is to search for evidence of strong, globally organized fields at the surface of $\gamma$ Dor pulsators. Methods. We identified objects consistent with being $\gamma$ Dor pulsators based on an analysis of space photometry from the Transiting Exoplanet Survey Satellite (TESS) mission. A spectropolarimetric survey was then conducted on a subset of 47 of these objects, with a precision sufficient to detect dipolar surface magnetic fields down to a threshold of about 10 -- 100 G. Results. We detected strong magnetism in three targets. However, upon closer inspection, none of these appear to be genuine $\gamma$ Dor pulsators. We found no evidence of surface magnetism in any of the remaining 44 objects. Conclusions. We conclude that either strong, globally organized magnetic fields and $\gamma$ Dor pulsation are mutually exclusive, or that such stars are exceedingly rare. A possible explanation is that strong global fields inhibit the excitation mechanism, which prevents $\gamma$ Dor pulsations from being driven in strongly magnetic intermediate-mass stars. The dipolar surface magnetic field strength upper limits we derive for this sample ($\lesssim$ 50 -- 100 G) provide valuable constraints for surface boundary conditions for asteroseismic models that include magnetism for $\gamma$ Dor stars.