Density distribution of the 6306 compact companion candidates in Galactic coordinates, coloured according to orbital period. The three sources discussed in Sect. 7 are shown in red. The 59 Galactic X-ray binaries are shown by blue points. The conspicuous circular hole between Galactic longitudes of ∼10 and ∼40 deg is due to the Gaia scan law and our imposed lower limit of 25 FoV transits.