Three QSOs acting as strong gravitational lenses

TL;DR

This paper reports the discovery of three new QSOs acting as strong gravitational lenses on background galaxies, confirmed through imaging and spectroscopy, with host galaxy properties comparable to known strong lenses.

Contribution

It introduces three newly identified QSO lenses using SDSS data, confirmed by Keck and HST imaging, expanding the sample of known strong gravitational lenses.

Findings

Three new QSO strong lenses discovered

Host galaxies have velocity dispersions of 210-285 km/s

Lenses are comparable in mass to SLACS sample

Abstract

We report the discovery of three new cases of QSOs acting as strong gravitational lenses on background emission line galaxies: SDSS J0827+5224 (zQSO = 0.293, zs = 0.412), SDSS J0919+2720 (zQSO = 0.209, zs = 0.558), SDSS J1005+4016 (zQSO = 0.230, zs = 0.441). The selection was carried out using a sample of 22,298 SDSS spectra displaying at least four emission lines at a redshift beyond that of the foreground QSO. The lensing nature is confirmed from Keck imaging and spectroscopy, as well as from HST/WFC3 imaging in the F475W and F814W filters. Two of the QSOs have face-on spiral host galaxies and the third is a QSO+galaxy pair. The velocity dispersion of the host galaxies, inferred from simple lens modeling, is between \sigma_v = 210 and 285 km/s, making these host galaxies comparable in mass with the SLACS sample of early-type strong lenses.