Simulated luminous binary population properties (orbital period P_orb, parallax ϖ, eccentricity e, angular photocenter orbit semimajor axis a₀, F146 magnitude, primary mass M₁, and mass ratio q) for the contiguous GBTDS fields. The solid black line denotes the distribution for all sources within 30 kpc. The dashed black line denotes the subset (∼80%) that are F146_Vega < 23.5 mag (source-dominated regime). The gray, blue, and red outlines denote the population of WD, NS, and BH binaries, respectively, with F146_Vega < 23.5 mag. Note that the primary is defined to be the brighter component of the binary, and the mass ratio is defined to be the ratio of the secondary to the primary; this can lead to q  >  1, especially in the case of BH+star binaries.