Mapping the Decline with Redshift of Dusty Star-forming Galaxies Using JWST and SCUBA-2

This is the authors' abstract. We don't add key points for this paper.

We use JWST NIRCam observations of the massive lensing cluster field A2744 to develop a red galaxy selection of f F444W > 1 μ Jy and f F444W / f F150W > 3.5 that picks out all nine >4.5 σ Atacama Large Millimeter/submillimeter Array 1.1 or 1.2 mm sources and 17 of the 19 >5 σ SCUBA-2 850 μ m sources in the covered areas. We show that by using the red galaxies as priors, we can probe deeper in the SCUBA-2 850 μ m image. This gives a sample of 44 >3 σ SCUBA-2 850 μ m sources with accurate positions, photometric redshifts, and magnifications. To investigate why our red galaxy selection picks out the 850 μ m sources, we next analyze an extended sample of 167 sources with f F444W > 0.05 μ Jy and f F444W / f F150W > 3.5. We find that the fainter f F444W sources in this sample are too faint to be detected in the SCUBA-2 850 μ m image. We also show that there is a strong drop between z < 4 and z > 4 (a factor of around 5) in the ratio of the far-infrared luminosity estimated from the 850 μ m flux to the ν L ν d (5000) at rest-frame 5000 Å. We argue that this result may be due to the high-redshift sources having less dust content than the lower-redshift sources.