Galaxy-scale lens search in the PEARLS NEP TDF and CEERS JWST fields

TL;DR

This paper reports the discovery of four galaxy-scale gravitational lenses in JWST fields, demonstrating JWST's high efficiency in detecting lenses and predicting a significant number of such lenses in future surveys.

Contribution

First JWST-based survey identifying galaxy-scale lenses in blank fields, with a novel lens detection method combining visual inspection and modeling, and estimates for future JWST lens yields.

Findings

Discovered 4 galaxy-scale lenses in JWST fields.

JWST can find about 1 lens per 3-4 NIRCam pointings.

A single JWST parallel survey could yield around 80 lenses.

Abstract

We present four galaxy scale lenses discovered in two JWST blank-fields: the ~ 54 arcmin^2 of the PEARLS North-Ecliptic-Pole Time-Domain Field (NEP TDF) and in the ~ 90 arcmin^2 of CEERS. We perform the search by visual inspection of NIRCam photometric data, obtaining an initial list of 16 lens candidates. We down-select this list to 5 high-confidence lens candidates, based on lens modelling of the image configuration and photometric redshift measurements for both the source and the deflector. We compare our results to samples of lenses obtained in ground-based and space-based lens searches and theoretical expectations. We expect that JWST observations of field galaxies will yield approximately 1 galaxy scale lens every three to four NIRCam pointings of comparable depth to these observations (~ 9 arcmin^2 each). This shows that JWST, compared to other lens searches, can yield an extremely high number of secure lenses per unit area, with redshift and size distributions complementary to lens samples obtained from ground-based and wide-area surveys. We estimate that a single JWST pure-parallel survey of comparable depth could yield $\sim 80$ galaxy scale lenses, with a third of them having z_lens>1 and z_source>3.