ALMA and JWST Identification of Faint Dusty Star-Forming Galaxies up to z~8

TL;DR

This study develops a new empirical method combining ALMA and JWST data to identify faint dusty star-forming galaxies up to redshift 8, revealing a population missed by previous surveys and suggesting evolutionary links to other galaxy types.

Contribution

The paper introduces a novel selection criterion based on I_star and color parameters, enabling detection of faint high-redshift dusty galaxies below previous detection limits.

Findings

Identified a faint population of high-redshift (z=6-8) DSFGs with average flux density 0.15 μJy.

Estimated a space density of approximately 6×10^-6 Mpc^-3 for these galaxies.

Proposed potential evolutionary connection between high-redshift UV-bright and dusty galaxies.

Abstract

We exploit a new sample of around 400 bright dusty galaxies from the ALMA CHAMPS Large Program, together with the rich JWST multi-band data products in the COSMOS field, to explore and validate new selection methods for identifying dusty star-forming galaxies (DSFGs). Here, we present an effective empirical selection criterion based on a newly defined parameter: I_star = log(M_star) x log(SFR). Incorporating the F277W-F444W color as a second parameter further improves the purity of the selection. We then apply this method to the COSMOS2025 catalog to search for fainter dusty galaxy candidates below the ALMA CHAMPS detection limit and, through a stacking technique, identify a population of high-redshift (z=6-8) DSFGs with an average flux density of$S_1.2mm = 0.15uJy and a space density of ~6E-6 Mpc^-3. This faint population seems to have been missed by most of the previous submillimeter/millimeter surveys, and ground- and space-based UV-to-NIR surveys. Finally, we discuss the possibility of an evolutionary connection between the z > 10 UV-bright galaxies recently discovered by JWST, the faint dusty z=6-8 galaxies identified here, and the population of z=3-5 massive quiescent galaxies, potentially linked as progenitor-descendant populations based on their abundance, redshifts, and stellar masses.