“School of Physic”
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| Paper IPM / Physic / 7363 |
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| Abstract: | |
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For searching gravitational microlensing events, millions of stars in
the Large Magellanic Cloud (LMC) have been monitored for one decade and
only a dozen of events have been detected. The low number of events
causes ambiguities in studying the mean mass of MACHOs and their
contribution to the Milky Way halo mass due to Poisson fluctuation. The
results obtained by the microlensing experiments, are in discrepancy
with other
observations in some cases. The outline of discrepancies are (i) the
incompatibility of the distribution of events duration in the galactic
models and observed data, (ii) the lack of abundant white dwarfs in the
galactic halo and (iii) undetected heavy elements in the galactic halo
that would be caused by the white dwarfs evolution and the supernova
explosions. Here we use the ansatz of a spatially varying mass function
of MACHOs and repeat the microlensing analysis. According to this
model, massive MACHOs reveal themselves more frequently in the
microlensing events than the brown dwarfs which have a higher
abundance. This point may resolve the mentioned contradictory between
the microlensing results and the other observations.
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