EXPECTED EAGLE EVENT RATE TOWARDS THE MAGELLANIC CLOUDS

We propose to search for MACHOs by observing EAGLE (Extremely Amplifie d Gravitational LEnsing) events of a majority of dim stars. This searc h is independent of the usual one. For the detection limit of EAGLE (s imilar to 20 mag), similar to 100 f (tau(LMC)/3 x 10(-7)) (100 days/[( t) over bar]) EAGLE events/y are expected to result from all the dim s tars in LMC. Here tau(LMC) and [(t) over bar] are the optical depth an d the average duration of microlensing events, respectively, while f ( 0 < f < 1) is a parameter depending on the unknown stellar luminosity function. The observed mean duration of EAGLE events also depends on t he luminosity function and is 0.01 similar to 0.4 times the usual dura tion of microlensing events, which corresponds to 1 similar to 30 days . The follow-up observation using larger telescopes may enable us to d etermine the impact parameter and the true duration of the event. If f is determined by another independent method, we can also determine ta u(LMC). Even if f is undetermined, the detection of EAGLE events stron gly suggest that MACHOs are not due to variable source stars, since EA GLE events are due to the dim main-sequence stars. Although for the SM C, the event rate is smaller by a factor of similar to 7, it is still a substantial number (similar to 13 f (tau(SMC)/3 x 10(-7)) (100 days/ [(t) over bar]) events/y).