Minimum as a function of the r-band magnitude for the BPS. Circles mark spectroscopic white dwarfs (H-dominated, orange; He-dominated, purple; and metal-polluted, black), and green squares show QSOs. The values obtained with and without the filters J0390 and J0410 for the calcium white dwarf 2243–4859 are connected by a black line. Those sources without Gaia DR3 parallax information are marked with a red dot. Those white dwarfs included in the Gentile Fusillo et al. (2021) catalog are marked with a white diamond. The black dashed line depicts the separation between white dwarfs and QSOs, . The dotted line shows the expected value for white dwarfs given the degrees of freedom in the analysis, .