Extending the MACHO Search to approximately 10 6 M sub sun

The search for a microlensing (changing light-curve) signature of massive compact halo objects (Machos) by the Macho Collaboration is currently believed to be sensitive in the range 10 -7 -10 2 M ⊙ . Microlensing events from higher mass objects last longer than the 4 yr duration of the planned experiments and therefore, according to current beliefs, cannot be distinguished from long-term variables. In fact the signature of Machos in the range 10 2 -10 3 M ⊙ can be distinguished from background events by the annual modulation in light magnification induced by the Earth's motion