(a) The ratio of the observed NUV flux to model-predicted NUV flux as a function of the fit_companion_mass. The horizontal orange dashed line marks F_NUV,obs/﹩{F}_{{\rm{NUV}},{\rm{mod}}}=1.2﹩, below which sources are considered to show no significant NUV excess and are directly retained. Sources with moderate excess, 1.2 < F_NUV,obs/﹩{F}_{{\rm{NUV}},{\rm{mod}}}\leqslant 3﹩, indicated by the area between the cyan dashed line and orange dashed line, are subjected to further diagnostics allowing for a luminous stellar companion. (b) The ratio of total model-predicted NUV flux (assuming an MS companion) to observed NUV flux as a function of the fit_companion_mass. The horizontal orange dashed line marks ﹩{F}_{{\rm{NUV}},{\rm{tot}}\_{\rm{mod}}}﹩/F_NUV,obs = 10, above which the predicted flux from a nondegenerate luminous companion severely exceeds the observed value, making such companions less possible.