Incident composite spectra from ultraviolet to near-infrared rest frame wavelengths. Final empirical stack (flux density values are reported in units of erg s⁻¹ cm⁻² Å⁻¹) for type 1 AGN covering the rest-frame wavelength range 700–36 000 Å. The main emission lines are marked. Shaded coloured regions mark the portion of the spectrum that will be covered by the low-resolution Euclid spectrograph up to redshift z = 9. All the incident spectra for the type 1 and type 2 AGN are available at the CDS. Bottom panel: final empirical stack (flux density values are reported in arbitrary units) for type 2 AGN (SB-AGN, SF-AGN, and AGN2) covering the rest-frame wavelength range 2000–28 000 Å.