On the detectability of strong lensing in near-infrared surveys

TL;DR

This paper estimates the frequency of strong gravitational lensing detectable in upcoming near-infrared surveys like JWST, VISTA, Euclid, and Roman, using realistic galaxy simulations and extending analysis into the near-infrared.

Contribution

It introduces a new methodology for lensing frequency estimation that does not assume lens properties and accounts for full galaxy morphologies in the near-infrared.

Findings

JWST could detect approximately 65 lensed systems in COSMOS-Web.

Forthcoming surveys may find 55-80% of lenses with multiple images.

High-redshift and dustier, more massive sources are likely to be detected in near-infrared surveys.

Abstract

We present new lensing frequency estimates for existing and forthcoming deep near-infrared surveys, including those from JWST and VISTA. The estimates are based on the JAdes extraGalactic Ultradeep Artificial Realisations (JAGUAR) galaxy catalogue accounting for the full photometry and morphologies for each galaxy. Due to the limited area of the JAGUAR simulations, they are less suited to wide-area surveys, however we also present extrapolations to the surveys carried out by Euclid and the Nancy Grace Roman Space Telescope. The methodology does not make assumptions on the nature of the lens itself and probes a wide range of lens masses. The lenses and sources are selected from the same catalogue and extend the analysis from the visible bands into the near-infrared. After generating realistic simulated lensed sources and selecting those that are detectable with SNR>20, we verify the lensing frequency expectations against published lens samples selected in the visible, finding them to be broadly consistent. We find that JWST could yield ~ 65 lensed systems in COSMOS-Web, of which ~ 25 per cent have source redshifts >4. Deeper, narrower programs (e.g. JADES-Medium) will probe more typical source galaxies (in flux and mass) but will find fewer systems (~ 25). Of the surveys we investigate, we find 55-80 per cent have detectable multiple imaging. Forthcoming NIR surveys will likely reveal new and diverse strong lens systems including lensed sources that are at higher redshift (JWST) and dustier, more massive and older (Euclid NISP) than those typically detected in the corresponding visible surveys.