Example BP/RP model spectra (left) and real spectra (right). All BP/RP spectra have been rescaled to an apparent magnitude of G = 15 in order to make their flux levels comparable. Panels (a) and (c) show the variation with T_eff, and panels (b) and (d) show the variation with A₀. Panels (a) and (b) show synthetic BP/RP spectra based on MARCS models (see Sect. 4.1). Panels (c) and (d) show BP/RP spectra obtained by Gaia where the APs were produced by the GSP-Phot module in the Apsis pipeline. BP spectra approximately cover the wavelength range from 325 nm to 680 nm and RP spectra from 610 nm to 1050 nm; see Fig. 5.