Full width at half maximum of the broad Hβ (left panels) and narrow [OIII]λ5007 (central panels) components of the Gaussian profiles modelling the emission lines in the AGN+hosts’ integrated-spectra at the different redshifts (see text). Right panel: equivalent-width ratio of the broad and narrow components. Different symbols indicate the distinct hosts (circles → NGC 809, triangles → PGC 055442, and squares → NGC 7119A), and their colours indicate the [OIII] luminosities of the AGN (black filled symbols → 10⁴², and blue open symbols → 10⁴³ erg s⁻¹). Error bars correspond to the uncertainties provided by the QSFIT¹³ package if larger than the symbol size. Dashed lines are the adopted values to simulate the emission of the central AGN (see Sect. 3.2). Grey bands indicate the parameters obtained when fitting the integrated spectra obtained from the mock HARMONI data for the pure AGN, enclosing the values and uncertainties for the two AGN luminosities.