HST observations of gravitationally lensed QSOs

TL;DR

HST observations have advanced our understanding of gravitationally lensed quasars by confirming lensing, detecting lensing galaxies, improving positional accuracy, and resolving extended structures, aiding in galaxy evolution studies and lens modeling.

Contribution

This paper presents high-resolution HST observations that enhance the identification, characterization, and analysis of gravitationally lensed quasars and their lensing galaxies.

Findings

Confirmed the lensed nature of multiple QSOs.

Detected and characterized lensing galaxies responsible for image splitting.

Resolved extended lensed structures such as rings and arcs.

Abstract

Thanks to its sharp view, HST has significantly improved our knowledge of tens of gravitationally lensed quasars in four different respects: (1) confirming their lensed nature; (2) detecting the lensing galaxy responsible for the image splitting; (3) improving the astrometric accuracy on the positions of the unresolved QSO images and of the lens; (4) resolving extended lensed structures from the QSO hosts into faint NIR or optical rings or arcs. These observations have helped to break some degeneracies on the lens potential, to probe the galaxy evolution and to reconstruct the true shape of the QSO host with an increased angular resolution.