Resolved fundamental metallicity relation for the star-forming spaxels of our sample. Here, log(Σ_*) is plotted against log(Σ_SFR) and each spaxel is color-coded by its gas-phase metallicity 12 + log(O/H). Additionally, an arrow angle and its error point to the direction of the steepest average gradient of increase of the local metallicity. Images are smoothed over via LOESS (Cappellari et al. 2013), a locally weighted regression method to compute mean trends of the population from noisy data.