Improved Determination of X-ray Fluxes of Quadruply Gravitationally Lensed Quasars

Chandra observations of quadruply gravitationally lensed quasars have a unique power to address several fundamental astrophysical issues. These observations have been used to (1) determine the cause of flux ratio anomalies, (2) measure the sizes of quasar accretion disks, (3) determine the dark matter content of the lensing galaxies, and (4) measure the stellar mass-to-light ratio (in fact, this is the only way to measure the stellar mass-to-light ratio beyond the solar neighborhood). These results rely on a determination of the four fluxes of the individual images of the lensed quasar. We have investigated improvements of our method to determine the individual fluxes and the flux ratios, and we present the results of our investigation for both the previously observed lensed quasars as well as preliminary results on new observations of recently discovered quadruply lensed quasars.