β as a function of redshift. Grey contours show the full JADES/A³COSMOS sample, while purple circles show the median position in several redshift bins. Different samples from the literature are shown in shades of blue (Laporte et al. 2017, 2019; Tamura et al. 2019; Inami et al. 2022; Mitsuhashi et al. 2024; Schouws et al. 2025; Topping et al. 2024). The inset panel shows the distribution of the intrinsic UV slope, β₀, allowed by the models (dark blue), as well as β₀ and β obtained from the SED fitting.