AAS Meeting #193 - Austin, Texas, January 1999
Session 117. Gravitational Lensing
Oral, Saturday, January 9, 1999, 2:00-3:30pm, Ballroom B

[Previous] | [Session 117] | [Next]

[117.04] Twinkle Twinkle Lensing Star, How I Wonder Where You Are

K.C. Sahu (STScI)

After five years of monitoring of millions of stars towards the Magellanic Clouds, detection of more than a dozen microlensing events, and independent knowledge on the lens location in three events, there is as yet no general consensus on the location of the lenses. In all three cases where there is some independent information on the lens location (two towards the SMC and one towards the LMC), the lenses seem to be within the Magellanic Clouds. But while the SMC events can be adequately explained by stars within the SMC, there have always been concerns that the stellar mass of the LMC may not be enough to account adequately for the observed events. A review of the structure of the LMC indicates that it is more complex than usually assumed for calculations of the microlensing optical depth. I will argue that if the physical depth of the LMC is larger than previously assumed, and/or if the LMC has a multi-layered structure as some of the observations imply, than the microlensing optical depth due to lensing by stars within the Large Magellanic Cloud is in fact enough to account for all the observed microlensing events.

The author(s) of this abstract have provided an email address for comments about the abstract: ksahu@stsci.edu

[Previous] | [Session 117] | [Next]