Astrometry with the MACHO Data Archive. I. High Proper Motion Stars toward the Galactic Bulge and Magellanic Clouds

We present the preliminary results of our astrometric study of stellar motions along the lines of sight of the Magellanic Clouds and the Galactic bulge. Using 5 years of MACHO project point-spread function photometry, we find that we can easily select stars with proper motions of 0.″03 yr-1 from these very dense fields, using the characteristic shapes of their light curves. By performing astrometry on photometrically selected, candidate, high proper motion (HPM) stars in 50 deg2, we have discovered 154 new HPM stars from ~55 million stars monitored by the MACHO project. These new objects have proper motions as high as 0.″5 yr-1, brightnesses ranging from V ~ 13 to V ~ 19, and V-R colors between 0.3 and 1.45.