Diagnostic analysis of CIII]λ1909 emission line. Left: Redshift evolution of the EW₀ of CIII]λ1909. The best-fit relation found by Roberts-Borsani et al. (2024) is indicated by the blue dashed line. We present both measurements and upper limits. The orange hexagons represent our results, while results from the literature are shown as grey circles (Arrabal Haro et al. 2023a; Bunker et al. 2023; D’Eugenio et al. 2024; Hsiao et al. 2024a; Goulding et al. 2023; Larson et al. 2023; Stiavelli et al. 2023; Williams et al. 2023; Boyett et al. 2024; Carniani et al. 2024; Castellano et al. 2024; Curti et al. 2024; Hainline et al. 2024; Schaerer et al. 2024; Witstok et al. 2024). Right: Diagnostic diagram based on CIII]λ1909 and CIVλλ1548,51 emission lines. The AGN and star-forming models from Nakajima & Maiolino (2022) are displayed as red squares and blue diamonds, respectively. We include a subset of the sources shown in the left plot, where measurements or limits for CIVλλ1548,51 are available.