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C. R. Burns (Swarthmore College), C. C. Dyer (University of Toronto)
To directly measure the shear produced by a gravitational lens, one must compare the intrinsic morphology of a background source with its observed (lensed) morphology. This is seldom possible for gravitational lenses at cosmological distances. However polarization, being invariant under gravitational lensing, can be used to measure the source plane morphology of background extended sources whose polarization is aligned with their intrinsic morphology (polarized radio jets, for instance). Comparing the morphology inferred from the polarization with the observed morphology can therefore yield constraints on the mass profiles of intervening matter. This is the only case where the weak lensing caused by a single galaxy can be measured directly. This technique therefore offers the potential of constraining the mass profiles and mass-to-light ratios of single galaxies. We present simulations of this weak lensing, discuss what parameters can be constrained and present observations of two weak lensing systems: 3C9 and PKS1229-021. In the case of 3C9, we can place limits on the mass-to-light ratios of two lensing galaxies and even constrain the core mass of the closer galaxy. In the case of PKS 1229-021, none of the observed foreground galaxies can produce the observed weak lensing and we therefore place upper limits on their masses. Further, we find that there must be a very dark object responsible for the observed lensing signal.
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The author(s) of this abstract have provided an email address for comments about the abstract: cburns1@swarthmore.edu
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.