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

Abstract

The James Webb Space Telescope is now detecting early black holes (BHs) as they transition from “seeds” to supermassive BHs. Recently, Bogdan et al. reported the detection of an X-ray luminous supermassive BH, UHZ-1, with a photometric redshift at z > 10. Such an extreme source at this very high redshift provides new insights on seeding and growth models for BHs given the short time available for formation and growth. Harnessing the exquisite sensitivity of JWST/NIRSpec, here we report the spectroscopic confirmation of UHZ-1 at z = 10.073 ± 0.002. We find that the NIRSpec/Prism spectrum is typical of recently discovered z ≈ 10 galaxies, characterized primarily by star formation features. We see no clear evidence of the powerful X-ray source in the rest-frame UV/optical spectrum, which may suggest heavy obscuration of the central BH, in line with the Compton-thick column density measured in the X-rays. We perform a stellar population fit simultaneously to the new NIRSpec spectroscopy and previously available photometry. The fit yields a stellar-mass estimate for the host galaxy that is significantly better constrained than prior photometric estimates ( M ⋆ ∼ 1.4 − 0.4 + 0.3 × 10 8 M ⊙). Given the predicted BH mass (M BH ∼ 107–108 M ⊙), the resulting ratio of M BH/M ⋆ remains 2 to 3 orders of magnitude higher than local values, thus lending support to the heavy seeding channel for the formation of supermassive BHs within the first billion years of cosmic evolution.

A JWST/NIRSpec First Census of Broad-line AGNs at z = 4–7: Detection of 10 Faint AGNs with M BH ∼ 106–108 M ⊙ and Their Host Galaxy Properties

“…NIRSpec IFU observations have revealed broad Hα and Hβ emission lines in a galaxy at z = 5.55 (Übler et al 2023), which is interpreted as a type 1.8 AGN with a black hole mass of M BH ∼ 10 8 M e . Very recently, Larson et al (2023) reported a broad Hβ emission line in a galaxy at z spec = 8.7, suggesting an SMBH whose mass is M BH ∼ 10 7 M e 570 Myr after the Big Bang (see also Bogdan et al 2023;Goulding et al 2023;Greene et al 2023;Fujimoto et al 2023;Kokorev et al 2023;Labbe et al 2023;Maiolino et al 2023;Matthee et al 2023 for studies that appeared after our initial submission of this paper).…”

The UNCOVER Survey: A First-look HST+JWST Catalog of Galaxy Redshifts and Stellar Population Properties Spanning 0.2 ≲ z ≲ 15

“…For the first time, it is possible to observe galaxies and candidates spanning 0.2  z  15 and infer their stellar population properties. In the context of UNCOVER, spectroscopically confirmed galaxies at z > 12 and an X-ray luminous supermassive black hole at z = 10.1 are studied in detail in Wang et al (2023a) and Goulding et al (2023), respectively, whereas a systematic search for z spec  9 sources is carried out in Fujimoto et al (2023b). The core of this paper is to present a galaxy catalog containing key stellar population metrics over the full dynamic range probed by the survey.…”

Constraining the AGN Luminosity Function from JWST with the X-Ray Background

“…A large number of faint AGN have also been identified at z ∼ 4-7 (e.g., Harikane et al 2023;Kocevski et al 2023;Maiolino et al 2023a;Matthee et al 2023;Onoue et al 2023;Übler et al 2023), with steeper faint ends in their luminosity functions than expected from extrapolating previous results. Such candidates are also detected out to higher redshifts, z ∼ 9-12 (Fudamoto et al 2022;Goulding et al 2023;Larson et al 2023;Maiolino et al 2023b). Recently, the EPOCHS survey covering the JWST PEARLS and Early Release Observations (EROs) fields identified nine new AGN in the 6.5 < z < 12 redshift range (Juodžbalis et al 2023), and the UNCOVER survey used the JWST NIRSpec to provide the UV luminosity functions from 15 AGN candidates over z ∼ 4-8 (Greene et al 2023).…”