학술논문
Uncovering a Massive z~7.7 Galaxy Hosting a Heavily Obscured Radio-Loud QSO Candidate in COSMOS-Web
Document Type
Working Paper
Author
Lambrides, Erini; Chiaberge, Marco; Long, Arianna; Liu, Daizhong; Akins, Hollis B.; Ptak, Andrew F.; Andika, Irham Taufik; Capetti, Alessandro; Casey, Caitlin M.; Champagne, Jaclyn B.; Chworowsky, Katherine; Clarke, Tracy E.; Cooper, Olivia R.; Ding, Xuheng; Dong, Dillon Z.; Faisst, Andreas L.; Forman, Jordan Y.; Franco, Maximilien; Gillman, Steven; Gozaliasl, Ghassem; Hall, Kirsten R.; Harish, Santosh; Hayward, Christopher C.; Hirschmann, Michaela; Hutchison, Taylor A.; Jahnke, Knud; Jin, Shuowen; Kartaltepe, Jeyhan S.; Kleiner, Emma T.; Koekemoer, Anton M.; Kokorev, Vasily; Manning, Sinclaire M.; Martin, Crystal L.; McKinney, Jed; Norman, Colin; Nyland, Kristina; Onoue, Masafusa; Robertson, Brant E.; Shuntov, Marko; Silverman, John D.; Stiavelli, Massimo; Trakhtenbrot, Benny; Vardoulaki, Eleni; Zavala, Jorge A.; Allen, Natalie; Ilbert, Olivier; McCracken, Henry Joy; Paquereau, Louise; Rhodes, Jason; Toft, Sune
Source
Subject
Language
Abstract
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 ($f_{1.28 \mathrm{GHz}} \sim 2$ mJy, $q_{24\mu m} = -1.1$, $\alpha_{1.28-3\mathrm{GHz}}=-1.2$, $\Delta \alpha = -0.4$). 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 (N$_{\mathrm{H}} > 10^{23}$ cm$^{-2}$). Using the wealth of deep UV to sub-mm photometric data, we report a singular solution photo-z of $z_\mathrm{phot}$ = 7.7$^{+0.4}_{-0.3}$ and estimate an extremely massive host-galaxy ($\log M_{\star} = 11.4 -12\,\mathrm{M}_{\odot}$) hosting a powerful, growing SMBH (L$_{\mathrm{Bol}} = 4-12 \times 10^{46}$ 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.
Comment: Accepted to ApJL
Comment: Accepted to ApJL