Distribution of the differences between Gaia and VLBA positions. The central panel shows the offsets in right ascension and declination for three categories of sources: single stars (black circles), sources with RUWE > 1.4 (red stars), and sources identified as multiple systems (green crosses). The red ellipse represents a 3σ contour derived from a 2D Gaussian fit to the single-star and RUWE ≤1.4 distributions. The top and right panels display the corresponding histograms of offsets in right ascension and declination, respectively, for single stars, and RUWE ≤1.4. Dashed red lines show the best-fit Gaussian models, with the fitted mean and standard deviation indicated in each subplot.