We monitored 8.6×106 stars in the Large Magellanic Cloud for 1.1 years and have found three events consistent with gravitational microlensing. We place strong constraints on Galactic halo lensing objects in the mass range 10-4Msolar to 10-1Msolar. Three events are fewer than expected for a standard spherical halo of objects in this mass range, but appear to exceed the number expected from known Galactic populations. Fitting a naive spherical halo model to our data yields a MACHO fraction f of massive compact halo objects (MACHOs), f = 0.19+0.16-0.10, a total MACHO mass (inside 50 kpc) of 7.6+6-4×1010Msolar, and a microlensing optical depth 8.8+7-5×10-8 (68% C.L.).
Physical Review Letters
- Pub Date:
- April 1995
- High Energy Physics - Phenomenology
- 8 pages, uuencoded compressed PostScript, 4 figures included (400kB). Submitted to Phys Rev Lett.