Histograms of Gaia EDR3 parameters for samples S1, S3, and S4, based on the ‘correlation’ method (Sect. 3.3 ii)). The plotted histograms contain an equal number of sources from each sample. The red, green, and blue histograms are for stars for which the Δ(CduC-Gaia) coordinate distance is <0.1″, between [0.25, 0.4]″, and >0.4″, respectively. The Gaia parameters are ruwe (a), parallax (b), parallax error (c), proper motion error (d), astrometric_excess_noise (the disagreement, expressed as an angle, between the observations of a source and the best-fitting standard astrometric model (e)), astrometric_excess_noise_sig (significance of excess noise (f)), error of RA and Dec coordinates at epoch J2016 (g), visibility_periods_used (number of visibility periods used in astrometric solution (h)), astrometric_n_bad_obs_al/astrometric_n_good_obs_al (the number of the bad AL (along-scan) observations divided by the number of the good AL observations (i)), astrometric_sigma5d_max (the longest semi-major axis of the 5-day error ellipsoid (j)), ipd_gof_harmonic_amplitude (a large value indicates that the source is double (k)), ipd_frac_multi_peak (fraction of observation windows indicating that the detection may be a resolved double star, either an optical pair or a physical binary (l)), and ipd_frac_odd_win (a high value indicates that a source is disturbed by nearby sources in a crowded field or due to a nearby bright (G < 13 mag) source (m)). The histograms of proper motion error (d) and RA and Dec coordinate error (i) include errors along RA and Dec separately, and thus they have lower noise than the other histograms.