The stellar activity index S _ph vs. Rossby number for 1023 stars in our Gold sample with periods greater than 10 days, plotted over the Kepler sample of Santos et al. (2019, 2021) and Mathur et al. (2023). As expected from theory and as seen in the Kepler field, photometric activity decreases with increasing Rossby number. The gray region denotes our measured TESS noise floor, ranging from 250 ppm at 8th magnitude to 1100 ppm at 13th magnitude. We do not detect TESS stars with amplitudes as low as Kepler due to TESS’s worse photometric precision and therefore higher noise floor.