The MACHO Project 5.7 Year LMC Results

The MACHO collaboration has analyzed 5.7years of photometry on approximately 11.7 million stars in the Large Magellanic Cloud (LMC) in a search for gravitational microlensing events. Two sets of cuts were used in the event selection process, and 13 and 17 events were found in the different sets. If the lenses are in the Galactic halo, then likelihood analysis for a standard halo model gives a halo mass fraction of about 0.2 with a 95% confidence interval of 0.08–0.5 and lens masses in the range 0.15–0.9 M⊙.