Going deeper into the dark with COSMOS-Web JWST unveils the total contribution of radio-selected NIR-faint galaxies to the cosmic star formation rate density

Abstract

We present the first follow-up with JWST of radio-selected near-infrared (NIR)-faint galaxies as part of the COSMOS-Web survey. By selecting galaxies detected at radio frequencies (S3 GHz > 11.5 µJy; i.e., S/N > 5) and with faint counterparts at NIR wavelengths (F150W > 26.1 mag), we collected a sample of 127 likely dusty star-forming galaxies (DSFGs). We estimated their physical properties through SED fitting, computed the first radio luminosity function for these types of sources and their contribution to the total cosmic star formation rate density. Our analysis confirms that these sources represent a population of highly dust-obscured (hAvi ∼ 3.5 mag) massive (hM?i ∼ 1010.8 M) and star-forming galaxies (hSFRi ∼ 300 M yr−1) located at hzi ∼ 3.6, representing the high-redshift tail of the full distribution of radio sources. Our results also indicate that these galaxies could dominate the bright end of the radio luminosity function and reach a total contribution to the cosmic star formation rate density equal to that estimated only considering NIR-bright sources at z ∼ 4.5. Finally, our analysis further confirms that the radio selection can be employed to collect statistically significant samples of DSFGs, representing a complementary alternative to the other selections based on JWST colors or detection at FIR/(sub)millimeter wavelengths.