Previous | Session 28 | Next
M.S. Peeples, P.L. Schechter (MIT), J.K. Wambsganss (ARI)
Simple models of lensing potentials that accurately reproduce positions for quadruply-imaged systems often fail miserably at reproducing flux ratios. As the light from each image passes through a different starfield in the lensing galaxy, these flux ratio anomalies might be due to micro-lensing by stars. Modelling the lens galaxy as an isothermal sphere with an external shear and a mass distribution that varies by the percentage of matter that is dark (i.e., continuous) or contained in stars (i.e., clumpy), we have simulated the distribution of possible magnification deviations from the underlying smooth potential. These distributions were then used to generate simulated pictures of possible configurations for several quadruply-imaged systems, including the most anamalous system known, SDSS0924+0219. In SDSS0924, component D is predicted to have a flux of about ten times what it does, about the same as component A. We find that anomalies this extreme are quite unlikely if none of the mass is continuously distributed, but much more likely if 80% of the mass is dark. We also present possible futures for PG1115+080, which has a configuration similar to that of SDSS0924, but the magnifications of all four images are currently close to what the models predict. Because the starfields associated with each component will change over time, we predict that image D in SDSS0924 will become as bright as A. If 80% of the surface density at the position of the lens is dark, we predict that for PG1115, image A2 will be found to have a substantial fraction of its time fainter than A1. We gratefully acknowledge support under NSF grant AST-0206010.
If you would like more information about this abstract, please follow the link to http://mollishka.mit.edu/lenses/. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.
Previous | Session 28 | Next
Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.