Top panel: UV Eddington luminosity L_UV/L_Edd ≡ Γ_UV as a function of bolometric Eddington luminosity L/L_Edd ≡ Γ for a Shakura & Sunyaev (1973) accretion disk around nine different black hole masses, from 10² M_⊙ to 10¹⁰ M_⊙; the case M_BH = 10⁸ M_⊙ is plotted with a dashed line. Bottom panel: circular velocity at the radius where the disk temperature T = 50 000 K or T = T_max if T_max <  50 000 K, as a function of Γ_UV, for the same nine values of M_BH as in the top panel.