Best-fit to the high resolution data of NGC 4594 (left), consisting on a broken power-law (dashed-black line) plus a simulated accretion disc (dash-dotted blue line). The sum of both contributions (dashed-red line) is used as input ionising radiation field for the CLOUDY simulations. Vertical coloured lines mark the ionisation energy of the ionic species used in the diagnostics diagrams. The disc assumes an inner (truncation) radius of 10 r_g, and an accretion rate of ṁ = 3 × 10⁻⁵ ṁ_Edd for a BH mass M_BH = 10⁹ M_⊙. A similar analysis is done for the quasar 3C 273 (right). Disc parameters: inner radius = 6 r_g, ṁ = 0.2 ṁ_Edd and M_BH = 7 × 10⁸ M_⊙.