2023/08/24 by Erini Lambrides, Marco Chiaberge, Lambrides, Erini +97 · 2 voices
#astro-ph.GA
paper · pdf · doi:10.48550/arxiv.2308.12823
In this letter, we report the discovery of the highest redshift, heavily obscured, radio-loud AGN candidate selected using JWST NIRCam/MIRI, mid-IR, sub-mm, and radio imaging in the COSMOS-Web field. Using multi-frequency radio observations and mid-IR photometry, we identify a powerful, radio-loud (RL), growing supermassive black hole (SMBH) with significant spectral steepening of the radio SED (f1.28 GHz ∼ 2 mJy, q24μm = -1.1, α1.28-3GHz=-1.2, Δα= -0.4). In conjunction with ALMA, deep ground-based observations, ancillary space-based data, and the unprecedented resolution and sensitivity of JWST, we find no evidence of AGN contribution to the UV/optical/NIR data and thus infer heavy amounts of obscuration (NH > 1023 cm-2). Using the wealth of deep UV to sub-mm photometric data, we report a singular solution photo-z of zphot = 7.7+0.4-0.3 and estimate an extremely massive host-galaxy (log M⋆ = 11.4 -12 M\odot) hosting a powerful, growing SMBH (LBol = 4-12 × 1046 erg s-1). This source represents the furthest known obscured RL AGN candidate, and its level of obscuration aligns with the most representative but observationally scarce population of AGN at these epochs.