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

Abstract

We report the discovery of an accreting supermassive black hole at z = 8.679. This galaxy, denoted here as CEERS_1019, was previously discovered as a Lyα-break galaxy by Hubble with a Lyα 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 Hβ line is best fit by a narrow plus a broad component, where the latter is measured at 2.5σ with an FWHM ∼1200 km s−1. 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 (M BH/M ⊙) = 6.95 ± 0.37, and we estimate that it is accreting at 1.2 ± 0.5 times the Eddington limit. The 1–8 μm photometric spectral energy distribution shows a continuum dominated by starlight and constrains the host galaxy to be massive (log M/M⊙ ∼9.5) and highly star-forming (star formation rate, or SFR ∼ 30 M⊙ yr−1; log sSFR ∼ − 7.9 yr−1). The line ratios show that the gas is metal-poor (Z/Z ⊙ ∼ 0.1), dense (n e ∼ 103 cm−3), and highly ionized (log U ∼ − 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.

UNCOVER: The Growth of the First Massive Black Holes from JWST/NIRSpec—Spectroscopic Redshift Confirmation of an X-Ray Luminous AGN at z = 10.1

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“…This release represents one of the first public MIRI surveys. Our data set has already enabled some pioneering studies covering the topics of, e.g., high-redshift AGNs, galaxy morphology, and early galaxy evolution (e.g., Barro et al 2023;Kirkpatrick et al 2023;Larson et al 2023;Magnelli et al 2023;Papovich et al 2023;Shen et al 2023;Yang et al 2023). In the future, researchers can explore their science topics with our reduced MIRI data products of CEERS.…”

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