Something Bright at the Edge of Everything: A Uniquely JWST-Dark Radio Source in COSMOS

TL;DR

This paper reports the discovery of a unique JWST-dark radio source in COSMOS, undetected across multiple wavelengths but visible in radio, potentially representing an extremely dust-obscured galaxy or a detached radio lobe.

Contribution

It presents the first identification of a JWST-dark radio source using combined radio and JWST data, revealing new discovery opportunities at the intersection of deep radio surveys and JWST imaging.

Findings

The source is undetected in all JWST, HST, Chandra, Herschel, and ALMA imaging.

It is detected in LOFAR 144 MHz and VLA 3 GHz radio data.

The source may be an extremely dust-obscured galaxy or a detached radio lobe.

Abstract

For decades, astronomers have been searching for bright radio sources deep into the epoch of reionization (EoR). The most distant, powerful radio sources are expected to reside in heavily dust-obscured galaxies, exceedingly faint at optical and infrared wavelengths. Motivated by this, I systematically cross-match radio and JWST source catalogs in the COSMOS field and identify a uniquely JWST-dark radio source: the only object undetected in every JWST band, yet clearly detected in radio data from LOFAR 144 MHz to the VLA 3 GHz. The source is only marginally resolved and shows a steep, unbroken radio spectrum, while remaining undetected in all available HST, JWST, Chandra, Herschel, and ALMA imaging. It may represent an extremely dust-obscured radio-loud source at cosmic dawn, or alternatively a detached radio lobe whose host galaxy lies elsewhere. In either case, it highlights the new discovery space at the intersection of deep radio surveys and JWST imaging.