1994, Astrophys. J. Letters , 435, L113
he analysis of the first 2 years of data from the Optical Gravitational Lensing Experiment (OGLE) project revealed nine microlensing events of the Galactic bulge stars, with the characteristic timescales in the range 8.6 days less than t(sub 0) less than 62 days, where t(sub 0) = R(sub E)/V. The optical depth to microlensing is larger than (3.3 +/- 1.2) x 10(exp -6), in excess of current theoretical estimates, indicating a much higher efficiency for microlensing by either bulge or disk lenses. We argue that the lenses are likely to be ordinary stars in the Galactic bar, which has its long axis elongated toward us. A relation between t(sub 0) and the lens masses remains unknown until a quantitative model of bar microlensing becomes available. At this time we have no evidence that the OGLE events are related to dark matter. The geometry of lens distribution can be determined observationally when the microlensing rate is measured over a large range of Galactic longitudes, like -10 deg less than l less than 10 deg, and the relative proper motions of the Galactic bulge (bar) stars are measures with the Hubble Space Telescope.
PostScript version available from astro-ph/9407010