X-ray bolometric correction () as a function of L_bol and λ_Edd. Left: vs. L_bol for a compilation of broad-line mostly high-z QSOs and local AGN. The sources are reported as in Fig. 4. Lower limits for the HYPERION QSOs are estimated assuming a power-law with fixed Γ = 2.4 (see Sect. 3 and Table 4). We also added COSMOS Type 1 AGN (pink dots) from Lusso et al. (2010). Solid and dashed black lines represent the fitting relation reported in Duras et al. (2020) and its 1σ spread. Dotted lines report the fixed value of 2–10 keV luminosity in units of erg s⁻¹ in the vs. L_bol plane. Right: vs. λ_Edd for the same sources reported in the left panel and with SMBH measurements available. Solid and dashed black lines represent the fitting relation reported in Duras et al. (2020) and its 1σ spread.