New near-infrared observations and lens-model constraints for UM673

TL;DR

This paper presents new near-infrared observations and lens-model constraints for the gravitational lens system UM673, including detailed photometry, flux ratio analysis, and discussion of lens models based on recent high-resolution data.

Contribution

The study provides the first high-resolution adaptive optics H-band images and comprehensive near-infrared photometry for UM673, refining flux ratios and lens model constraints.

Findings

Estimated extinction-corrected flux ratio of 2.14 mag between components A and B.

Presented new high-resolution H-band images of UM673.

Analyzed flux ratios across multiple bands to understand lensing and extinction.

Abstract

Aims: We performed a detailed photometric analysis of the lensed system UM673 (Q0142-100) and an analysis of the tentative lens models. Methods: High-resolution adaptive optics images of UM673 taken with the Subaru telescope in the H band were examined. We also analysed the J, H and K-band observational data of UM673 obtained with the 1.3m telescope at the CTIO observatory. Results: We present photometry of quasar components A and B of UM673, the lens, and the nearby bright galaxy using H-band observational data obtained with the Subaru telescope. Based on the CTIO observations of UM673, we also present J- and H-band photometry and estimates of the J, H and K-band flux ratios between the two UM673 components in recent epochs. The near-infrared fluxes of the A and B components of UM673 and their published optical fluxes are analysed to measure extinction properties of the lensing galaxy. We estimate the extinction-corrected flux ratio between components A and B to be about 2.14 mag. We discuss lens models for the UM673 system constrained with the positions of the UM673 components, their flux ratio, and the previously measured time delay