Top panel: Eddington ratio λ = L_d/L_Edd as a function of the BH spin a for different viewing angles (θ_v = 0° black, 30° red, 45° blue) computed with the KERRBB (solid lines) and the SLIMBH (dashed lines) models for the source J1342. Central and bottom panels: same plot for the sources J1120 and J0038. The black dotted line is the thin disk limit for λ following Laor & Netzer (1989): the KERRBB solutions above this limit are not consistent with the thin disk approximation and another model (e.g. slim disk) must be used.