Ionic electron temperature across all SFR–M_⋆ and radial bins as a function of strong-line metallicity (P04). The two panels present identical temperature estimates. In the upper panel, OIII and SIII temperatures are binned in metallicity intervals of 0.05 dex; filled regions represent the 1σ percentile of distributions around the median values indicated by solid lines. The same binning procedure is applied to the low-ionization ionic temperatures in the lower panel. The error bars for OII, SII, and NII temperatures in the upper panel as well as OIII and SIII in the lower one correspond to the formal error obtained through the bootstrapping analysis, as detailed in Sect. 3.3.