Spectral photon index, Γ, as a function of n_Edd. In the top panel, different symbols correspond to different redshift intervals, as indicated in the legend. The results are colour-coded based on the N_H values of the sources. The p-values obtained by applying a Spearman correlation analysis are shown in the legend. The bottom panel shows the same relation but for X-ray AGN with N_H > 10²² cm⁻² (red circles) and AGN with N_H < 10²² cm⁻² (blue triangles). The p-values for the Γ − n_Edd correlation for each AGN population are presented in the legend of the plot. The different lines correspond to the best fits using the total AGN sample (black dashed line), AGN with N_H > 10²² cm⁻² (red solid line), and AGN with N_H < 10²² cm⁻² (blue line).