PKS 1830-211 as a Gravitationally Lensed System

The unusually strong, flat-spectrum, 1" separation double radio source, PKS 1830-211, which has been found to exhibit a connecting radio ringlike feature, is believed to be a gravitationally lensed system. It is attempted here to reconcile the available multifrequency radio observations with the lensing hypothesis. The source can be modeled as a core-knot-jet structure; this suggests an explanation for the differing radio spectra of the two dominant features which are believed to be images of the compact part of the source. Simulations of the extended structure at 8 GHz and 15 GHz are presented. Our model of the system indicates that a faint feature that has shown up in previous observations is probably a combined third/fifth image of some portions of the source. It is suggested that intrinsic variability in the angle of polarization and the percentage polarization of the polarized emission from the compact source, as viewed through its images, could be used as a means of determining the time delay between the images.