UV diagnostic diagram. Small green and red empty symbols represent model predictions for SFGs and AGNs, respectively, from Nakajima & Maiolino (2022). See the legend for details about model parameters. Large circles refer to the MUSE measurements of the three sources in our sample, as labelled; MUSE resolution does not allow us to separate the contribution of primary and secondary AGNs, but GS551 and GS10578 line ratios are likely dominated by the primary (brightest) AGN. The figure also shows individual X-ray AGNs (diamonds) and measurements from stacked AGN spectra (crosses), as well as SFGs at z ∼ 3 from the literature (green squares; see Sect. 5.2). GS551, GS10578 and LAE2 occupy the AGN region of the diagram.