Gaia GraL: Gaia DR2 Gravitational Lens Systems. VI. Spectroscopic\n Confirmation and Modeling of Quadruply-Imaged Lensed Quasars

Abstract

Combining the exquisite angular resolution of Gaia with optical light curves\nand WISE photometry, the Gaia Gravitational Lenses group (GraL) uses machine\nlearning techniques to identify candidate strongly lensed quasars, and has\nconfirmed over two dozen new strongly lensed quasars from the Gaia Data Release\n2. This paper reports on the 12 quadruply-imaged quasars identified by this\neffort to date, which is approximately a 20% increase in the total number of\nconfirmed quadruply-imaged quasars. We discuss the candidate selection,\nspectroscopic follow-up, and lens modeling. We also report our spectroscopic\nfailures as an aid for future investigations.\n