Spatial distributions of subsamples selected according to various criteria. Dashed squares are the Chandra FOVs. The color scale is the same for all panels. Panel a: all Gaia sources selected from proper motion alone, falling inside the rectangle in Fig. 7b. and errors on μ_α and μ_α less than 0.5. Top-axis colorbar as in Fig. 6. Panel b: Gaia sources selected from proper motion and parallax, falling inside both rectangles of Fig. 7b and c. Panel c: Gaia sources as in panel b, but missed by the X-ray, CTTS, and M-star selection methods. Panel d: M stars missed by the Gaia, X-ray, and CTTS selection methods.