Can MACHOs probe the shape of the galaxy halo?

Microlensing searches in our galaxy have recently discovered several candidates in the direction of the Large Magellanic Cloud (LMC). We study the prospects for such searches to yield useful information about the flattening of the Galaxy dark matter halo, using a self-consistent oblate halo model and allowing for the possibility of misalignment between the disk and halo symmetry axes. The microlensing optical depth for the LMC, τ(LMC), depends sensitively on the disk-halo tilt angle in the Milky Way, as does the ratio τ(SMC)/ τ(LMC). If the tilt angle is as large as 30°, a much larger spread in values for τ(LMC) is consistent with rotation curve constraints than previously thought. Disk-halo tilt and halo flattening do not significantly affect the MACHO masses inferred from event durations.