Repository logo
 

A CEERS Discovery of an Accreting Supermassive Black Hole 570 Myr after the Big Bang: Identifying a Progenitor of Massive z > 6 Quasars

Published version
Peer-reviewed

Repository DOI


Change log

Abstract

jats:titleAbstract</jats:title> jats:pWe report the discovery of an accreting supermassive black hole at jats:italicz</jats:italic> = 8.679. This galaxy, denoted here as CEERS_1019, was previously discovered as a Lyjats:italicα</jats:italic>-break galaxy by Hubble with a Lyjats:italicα</jats:italic> redshift from Keck. As part of the Cosmic Evolution Early Release Science (CEERS) survey, we have observed this source with JWST/NIRSpec, MIRI, NIRCam, and NIRCam/WFSS and uncovered a plethora of emission lines. The Hjats:italicβ</jats:italic> line is best fit by a narrow plus a broad component, where the latter is measured at 2.5jats:italicσ</jats:italic> with an FWHM ∼1200 km sjats:sup−1</jats:sup>. We conclude this originates in the broadline region of an active galactic nucleus (AGN). This is supported by the presence of weak high-ionization lines (N V, N IV], and C III]), as well as a spatial point-source component. The implied mass of the black hole (BH) is log (jats:italicM</jats:italic> jats:subBH</jats:sub>/jats:italicM</jats:italic> jats:sub⊙</jats:sub>) = 6.95 ± 0.37, and we estimate that it is accreting at 1.2 ± 0.5 times the Eddington limit. The 1–8 jats:italicμ</jats:italic>m photometric spectral energy distribution shows a continuum dominated by starlight and constrains the host galaxy to be massive (log M/Mjats:sub⊙</jats:sub> ∼9.5) and highly star-forming (star formation rate, or SFR ∼ 30 Mjats:sub⊙</jats:sub> yrjats:sup−1</jats:sup>; log sSFR ∼ − 7.9 yrjats:sup−1</jats:sup>). The line ratios show that the gas is metal-poor (jats:italicZ</jats:italic>/jats:italicZ</jats:italic> jats:sub⊙</jats:sub> ∼ 0.1), dense (jats:italicn</jats:italic> jats:sub jats:italice</jats:italic> </jats:sub> ∼ 10jats:sup3</jats:sup> cmjats:sup−3</jats:sup>), and highly ionized (log jats:italicU</jats:italic> ∼ − 2.1). We use this present highest-redshift AGN discovery to place constraints on BH seeding models and find that a combination of either super-Eddington accretion from stellar seeds or Eddington accretion from very massive BH seeds is required to form this object.</jats:p>

Description

Keywords

5101 Astronomical Sciences, 51 Physical Sciences

Journal Title

Astrophysical Journal Letters

Conference Name

Journal ISSN

2041-8205
2041-8213

Volume Title

953

Publisher

American Astronomical Society
Sponsorship
National Aeronautics and Space Administration (NASA) (NAS5-03127)
National Aeronautics and Space Administration (NASA) (JWST-ERS-01345)
National Aeronautics and Space Administration (NASA) (JWST-AR-02446)
NSF ∣ Directorate for STEM Education (EDU) (CAREER-1945546)
National Aeronautics and Space Administration (NASA) (HST-HF2-51505.001-A)
United States - Israel Binational Science Foundation (BSF) (2109066)