CAPERS-LRD-z9: A Gas-enshrouded Little Red Dot Hosting a Broad-line Active Galactic Nucleus at z = 9.288

CAPERS-LRD-z9: A Gas-enshrouded Little Red Dot Hosting a Broad-line Active Galactic Nucleus at z = 9.288

We present CAPERS-LRD-z9, a little red dot (LRD) that we confirm to be a z = 9.288 broad-line active galactic nucleus (BLAGN). First identified as a high-redshift LRD candidate from PRIMER NIRCam photometry, follow-up NIRSpec/PRISM spectroscopy of CAPERS-LRD-z9 from the CANDELS-Area Prism Epoch of R...

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Main Authors: Anthony J. Taylor, Vasily Kokorev, Dale D. Kocevski, Hollis B. Akins, Fergus Cullen, Mark Dickinson, Steven L. Finkelstein, Pablo Arrabal Haro, Volker Bromm, Mauro Giavalisco, Kohei Inayoshi, Stéphanie Juneau, Gene C. K. Leung, Pablo G. Pérez-González, Rachel S. Somerville, Jonathan R. Trump, Ricardo O. Amorín, Guillermo Barro, Denis Burgarella, Madisyn Brooks, Adam C. Carnall, Caitlin M. Casey, Yingjie Cheng, John Chisholm, Katherine Chworowsky, Kelcey Davis, Callum T. Donnan, James S. Dunlop, Richard S. Ellis, Vital Fernández, Seiji Fujimoto, Norman A. Grogin, Ansh R. Gupta, Nimish P. Hathi, Intae Jung, Michaela Hirschmann, Jeyhan S. Kartaltepe, Anton M. Koekemoer, Rebecca L. Larson, Ho-Hin Leung, Mario Llerena, Ray A. Lucas, Derek J. McLeod, Ross McLure, Lorenzo Napolitano, Casey Papovich, Thomas M. Stanton, Roberta Tripodi, Xin Wang, Stephen M. Wilkins, L. Y. Aaron Yung, Jorge A. Zavala
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal Letters
Subjects:
James Webb Space Telescope
Active galactic nuclei
AGN host galaxies
Supermassive black holes
Online Access:https://doi.org/10.3847/2041-8213/ade789
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Summary:We present CAPERS-LRD-z9, a little red dot (LRD) that we confirm to be a z = 9.288 broad-line active galactic nucleus (BLAGN). First identified as a high-redshift LRD candidate from PRIMER NIRCam photometry, follow-up NIRSpec/PRISM spectroscopy of CAPERS-LRD-z9 from the CANDELS-Area Prism Epoch of Reionization Survey (CAPERS) has revealed a broad 3500 km s ^−1 full width at half-maximum H β emission line and narrow [O iii ] λλ 4959, 5007 lines, indicative of a BLAGN. Based on the broad H β line, we compute a canonical black hole mass of ${\mathrm{log}}\,({M}_{{\rm{BH}}}/{M}_{\odot })=7.58\pm 0.15$ , although full consideration of systematic uncertainties yields a conservative range of $6.65\lt {\mathrm{log}}\,({M}_{{\rm{BH}}}/{M}_{\odot })\lt 8.50$ . These observations suggest that either a massive black hole seed or a lighter stellar remnant seed undergoing periods of super-Eddington accretion is necessary to grow such a massive black hole in ≲500 Myr of cosmic time. CAPERS-LRD-z9 exhibits a strong Balmer break, consistent with a central AGN surrounded by dense (∼10 ^10 cm ^−3 ) neutral gas. We model CAPERS-LRD-z9 using Cloudy to fit the emission redward of the Balmer break with a dense-gas-enshrouded AGN and bagpipes to fit the rest-ultraviolet emission as a host-galaxy stellar population. This upper limit on the stellar mass of the host galaxy (<10 ^9 M _⊙ ) implies that the black hole to stellar mass ratio may be extremely large, possibly >5% (although systematic uncertainties on the black hole mass prevent strong conclusions). However, the shape of the UV continuum differs from typical high-redshift star-forming galaxies, indicating that this UV emission may also be of AGN origin; hence, the true stellar mass of the host may be still lower.
ISSN:2041-8205

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