Spatially resolved fundamental metallicity relation (rFMR, Σ_* − Z − Σ_SFR) of star formation knots in NGC 4809/4810. The combined quantity μ_α is defined as log(Σ_*) − αlog(Σ_SFR). We adopt the α = 0.32, which is same to previous studies (e.g., Mannucci et al. 2010; Yao et al. 2022). The solid lines represent the best-fit relations based on orthogonal distance regression (odr). The dashed lines represent the 1σ distribution around the fitted FMR relations. The other markers are the same as in Fig. 7.