The Optical Gravitational Lensing Experiment.
Discovery of the First Candidate Microlensing Event
in the Direction of the Galactic Bulge.

Udalski A., Szymanski M., Kaluzny J., Kubiak M.,
Krzeminski W., Mateo M., Preston, G.W., and Paczynski B.

1993, Acta Astron., 43, 289.


We report discovery of the first candidate microlensing event to be dicovered in the direction of the Galactic Bulge. The peak brightness of the candidate event occurred on June 15, 1993. The event had time scale (R_0/V, R_0 - the Einstein radius, V - the transverse velocity of the lens) equal to 23.8 +/- 0.9 day and amplification A=2.4 +/- 0.1. The lensed star is at the turn-off point in the Galactic Bulge. The lensing object is likely to be a disk M-dwarf of about 0.3 solar mass.