Microlensing towards the LMC revisited by adopting a non-Gaussian
  velocity distribution for the sources
  We discuss whether the Gaussian is a reasonable approximation of the velocity
distribution of stellar systems that are not spherically distributed. By using
a non-Gaussian velocity distribution to describe the sources in the Large
Magellanic Cloud (LMC), we reinvestigate the expected microlensing parameters
of a lens population isotropically distributed either in the Milky Way halo or
in the LMC (self lensing). We compare our estimates with the experimental
results of the MACHO collaboration. An interesting result that emerges from our
analysis is that, moving from the Gaussian to the non-Gaussian case, we do not
observe any change in the form of the distribution curves describing the rate
of microlensing events for lenses in the Galactic halo. The corresponding
expected timescales and number of expected events also do not vary. Conversely,
with respect to the self-lensing case, we observe a moderate increase in the
rate and number of expected events. We conclude that the error in the estimate
of the most likely value for the MACHO mass and the Galactic halo fraction in
form of MACHOs, calculated with a Gaussian velocity distribution for the LMC
sources, is not higher than 2%.
