GRAVITATIONAL MICROLENSING BY THE MACHOS OF THE LARGE MAGELLANIC CLOUD

The expected microlensing events of the Large Magellanic Cloud (LMC) by the MACHOs of the LMC itself are calculated and compared with analog events by objects in the Galactic halo. The LMC matter distribution is modeled by a spherical halo and an exponential disk, while a face-on exponential disk is used for the stellar distribution of the LMC. Among the microlensing events discovered by the MACHO and EROS projects, a fraction of 22% could be caused by the lenses near the center of the LMC or 13% from lenses at 5 degrees from the LMC center, provided that the halo of the Galaxy and of the LMC are composed of MACHOs. The LMC disk produces a relatively lower optical depth to microlensing of similar to 3 x 10(-8) but contributes a fraction of similar to 40% of the observed microlensing events toward the LMC center, if the actual detection rate is taken to be (7-9) x 10(-8). It is then likely that the presently detected microlensing events near the center of the LMC are due to some combination of the MACHOs of the Galactic halo, the Galactic spheroid, the LMC halo, and particularly the LMC disk. Therefore, any statistical study of these microlensing events must take the LMC lenses into account.