出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We discuss whether the Gaussian is a reasonable approximation for the velocity distribution of
stellar systems that are not spherically distributed. In particular, 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) and 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 of the rate of microlening events for lenses in the Galactic halo. Moreover,
the corresponding expected timescales and the number of the expected events do not vary.
Conversely, with regard to the self-lensing case, we observe a moderate increase of the rate and
the number of expected events. The main conclusion is that the error on the estimate of the most
likely value for the MACHO mass as well as for the Galactic halo fraction in form of MACHOs,
calculated with a Gaussian velocity distribution for the LMC sources, is not grater than 2%.
