Proper motion space of the stars remaining after the selection procedure of Sect. 3. The data points within this space are attributed a score to belong to a 2-component Gaussian mixture trained on the distribution of stars in proper motion space shown in the lower left corner of Fig. 2. The data points are colored by the score (log likelihood) over the star’s positions in proper motion space, and contours of the log likelihood are also visualized. The contours pin-point the location and direction of the trained Gaussian distributions. We also show the centers of the two Gaussian distributions by the plus sign. The red contour corresponds to log likelihood >  − 1.75. All data points that fall within this contour are chosen and kept for any subsequent analysis.