Line ratio diagrams. This figure shows the position of GN-z11 (red star) on the R2–R3, R23–O32, O32–O3Hγ and O32–O33 diagrams. JWST-detected z > 8 galaxies are represented as filled circles. The blue and red markers represent the high-z SFGs and type 1 AGNs from different samples, respectively. Further details of these samples are presented in Sect. 3.3. The local low-metallicity subsample (gray markers), drawn from Izotov et al. (2006), Izotov & Thuan (2011), Izotov et al. (2016, 2019, 2024), was selected to be 12 + log(O/H) < 8. The JADES subsample, drawn from Bunker et al. (2023) and Cameron et al. (2023a), was selected to be z > 3. The dashed lines represent the separation between the AGN-dominant and the AGN+SFGs regions presented by Mazzolari et al. (2024). When no Hγ data were available, we considered Hγ = Hα/5.93.