Finding Lensed Radio Sources with the Very Large Array Sky Survey

Abstract Radio observations of strongly lensed objects are valuable as cosmological probes. Lensed radio sources have proven difficult to identify, in large part due to the limited depth and angular resolution of the previous generation of radio sky surveys, and, as such, only a few dozen lensed radio sources are known. In this work, we present the results of a pilot study, using the Very Large Array Sky Survey (VLASS) in combination with optical data to more efficiently identify lensed radio sources. We obtain high-resolution (0 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover> <mml:mrow> <mml:mo>.</mml:mo> </mml:mrow> <mml:mrow> <mml:mtext>″</mml:mtext> </mml:mrow> </mml:mover> </mml:math> 2) VLA follow-up observations for 11 targets that we identify using three different techniques: (i) a search for compact radio sources offset from galaxies with high lensing potential, (ii) VLASS detections of known lensed galaxies, and (iii) VLASS detections of known lensed quasars. Five of our targets show radio emission from the lensed images, including 100% of the lensed optical quasar systems. This work demonstrates the efficacy of combining deep- and high-resolution wide-area radio and optical survey data to efficiently find lensed radio sources, and we discuss the potential impact of such an approach using next-generation surveys with the Vera C. Rubin Observatory, Euclid, and Nancy Grace Roman Space Telescope.