  We discuss the results of the MEGA microlensing campaign towards M31. Our
analysis is based on an analytical evaluation of the microlensing rate, taking
into account the observational efficiency as given by the MEGA collaboration.
In particular, we study the spatial and time duration distributions of the
microlensing events for several mass distribution models of the M31 bulge. We
find that only for extreme models of the M31 luminous components it is possible
to reconcile the total observed MEGA events with the expected self-lensing
contribution. Nevertheless, the expected spatial distribution of self-lensing
events is more concentrated and hardly in agreement with the observed
distribution. We find it thus difficult to explain all events as being due to
self-lensing alone. On the other hand, the small number of events does not yet
allow to draw firm conclusions on the halo dark matter fraction in form of
MACHOs.
