SED fit for WD1. Filter-averaged fluxes converted from observed magnitudes are shown in different colors (Gaia in cyan, IGAPS in dark red, Pan-STARRS in red, and XMM-OM in magenta). The respective full widths at tenth maximum are shown as dashed horizontal lines. A pure He model with T_eff = 90 000 K and log ɡ = 8.3 that was interpolated from the grid computed in Reindl et al. (2023) and degraded to a spectral resolution of 6 Å is plotted in gray. To reduce the steep SED slope, the flux has been multiplied by the wavelength cubed. Bottom panel: Difference between synthetic and observed magnitudes.