Analyzing the Flux Anomalies of the Large-Separation Lensed Quasar SDSS J1029+2623

TL;DR

This study resolves the flux anomalies in the gravitational lens system SDSS J1029+2623 using high-resolution radio imaging, suggesting substructure near the lens can explain observed flux discrepancies.

Contribution

It introduces a detailed model incorporating substructure near the lens to explain flux anomalies, advancing understanding of mass distribution in lensing clusters.

Findings

Radio flux anomalies persist, indicating complex mass distribution.

Substructure of ~10^8 solar masses can account for flux discrepancies.

Positional offsets explain differences between optical and radio flux ratios.

Abstract

Using a high resolution radio image, we successfully resolve the two fold image components B and C of the quasar lens system SDSS J1029+2623. The flux anomalies associated with these two components in the optical regime persist, albeit less strongly, in our radio observations, suggesting that the cluster must be modeled by something more than a single central potential. We argue that placing substructure close to one of the components can account for a flux anomaly with negligible changes in the component positions. Our best fit model has a substructure mass of ~10^8 solar masses up to the mass-sheet degeneracy, located roughly 0.1 arcsecs West and 0.1 arcsecs North of component B. We demonstrate that a positional offset between the centers of the source components can explain the differences between the optical and radio flux ratios.