UNCOVER: A NIRSpec Identification of a Broad-line AGN at z = 8.50
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Kokorev, V.Fujimoto, S.

Labbe, I.
Greene, J.E.
Bezanson, R.
Dayal, P.
Nelson, E.J.
Atek, H.
Brammer, G.
Caputi, K.I.
Chemerynska, I.
Cutler, S.E.
Feldmann, R.
Fudamoto, Y.
Furtak, L.J.
Goulding, A.D.
de Graaff, A.
Leja, J.
Marchesini, D.
Miller, T.B.
Nanayakkara, T.

Oesch, P.A.
Pan, R.
Price, S.H.
Setton, D.J.
Smit, R.
Stefanon, M.
Wang, B.
Weaver, J.R.
Whitaker, K.E.
Williams, C.C.
Zitrin, A.
Affiliation
Steward Observatory, University of ArizonaIssue Date
2023-10-26
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American Astronomical SocietyCitation
Vasily Kokorev et al 2023 ApJL 957 L7Journal
Astrophysical Journal LettersRights
© 2023. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Deep observations with the James Webb Space Telescope (JWST) have revealed an emerging population of red pointlike sources that could provide a link between the postulated supermassive black hole seeds and observed quasars. In this work, we present a JWST/NIRSpec spectrum from the JWST Cycle 1 UNCOVER Treasury survey of a massive accreting black hole at z = 8.50 displaying a clear broad-line component as inferred from the Hβ line with FWHM = 3439 ± 413 km s−1, typical of the broad-line region of an active galactic nucleus (AGN). The AGN nature of this object is further supported by high ionization, as inferred from emission lines, and a point-source morphology. We compute a black hole mass of log 10 ( M BH / M ⊙ ) = 8.17 ± 0.42 and a bolometric luminosity of L bol ∼ 6.6 × 1045 erg s−1. These values imply that our object is accreting at ∼40% of the Eddington limit. Detailed modeling of the spectral energy distribution in the optical and near-infrared, together with constraints from ALMA, indicate an upper limit on the stellar mass of log 10 ( M * / M ⊙ ) < 8.7 , which would lead to an unprecedented ratio of black hole to host mass of at least ∼30%. This is orders of magnitude higher compared to the local QSOs but consistent with recent AGN studies at high redshift with JWST. This finding suggests that a nonnegligible fraction of supermassive black holes either started out from massive seeds and/or grew at a super-Eddington rate at high redshift. Given the predicted number densities of high-z faint AGN, future NIRSpec observations of larger samples will allow us to further investigate galaxy-black hole coevolution in the early Universe. © 2023. The Author(s). Published by the American Astronomical Society.Note
Open access journalISSN
2041-8205Version
Final Published Versionae974a485f413a2113503eed53cd6c53
10.3847/2041-8213/ad037a
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Except where otherwise noted, this item's license is described as © 2023. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence.