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Session 83 - Gravitational Lensing.
Display session, Friday, January 09
The microlensing surveys have been very successful: the phenomenon has been observed in stars in the Magellanic Clouds and the Galactic center. The rate and duration of the events have been used as a probe of the structure of the disk and bulge of the Galaxy, and have set stringent upper limits on the extent to which low mass MACHOs might contribute to the dark matter halo of the Galaxy. Exotic features in the light curves of lensing events that are detected in real time are being used to constrain the parameters of the lenses, to address questions in stellar astronomy, and to search for low mass planetary companions to the lensing objects. Variable star astronomy is also benefiting from photometric measurements of millions of stars over thousands of epochs. The MACHO collaboration has detected an excess of lensing events towards the LMC which is not accounted for by any known stellar population. Determining the nature and spatial distribution of this lensing population is a central question that will likely remain unresolved until more data are gathered. I will describe a next-generation microlensing project that is being designed to achieve a factor of ten increase in event rate over existing surveys, providing hundreds rather than tens of events towards the LMC and SMC, in order to determine the nature of this excess lensing population.
Program listing for Friday