The Astrophysical Journal Letters (Jan 2023)
Hidden Little Monsters: Spectroscopic Identification of Low-mass, Broad-line AGNs at z > 5 with CEERS
- Dale D. Kocevski,
- Masafusa Onoue,
- Kohei Inayoshi,
- Jonathan R. Trump,
- Pablo Arrabal Haro,
- Andrea Grazian,
- Mark Dickinson,
- Steven L. Finkelstein,
- Jeyhan S. Kartaltepe,
- Michaela Hirschmann,
- James Aird,
- Benne W. Holwerda,
- Seiji Fujimoto,
- Stéphanie Juneau,
- Ricardo O. Amorín,
- Bren E. Backhaus,
- Micaela B. Bagley,
- Guillermo Barro,
- Eric F. Bell,
- Laura Bisigello,
- Antonello Calabrò,
- Nikko J. Cleri,
- M. C. Cooper,
- Xuheng Ding,
- Norman A. Grogin,
- Luis C. Ho,
- Taylor A. Hutchison,
- Akio K. Inoue,
- Linhua Jiang,
- Brenda Jones,
- Anton M. Koekemoer,
- Wenxiu Li,
- Zhengrong Li,
- Elizabeth J. McGrath,
- Juan Molina,
- Casey Papovich,
- Pablo G. Pérez-González,
- Nor Pirzkal,
- Stephen M. Wilkins,
- Guang Yang,
- L. Y. Aaron Yung
Affiliations
- Dale D. Kocevski
- ORCiD
- Department of Physics and Astronomy, Colby College , Waterville, ME 04901, USA
- Masafusa Onoue
- ORCiD
- Kavli Institute for Astronomy and Astrophysics, Peking University , Beijing 100871, People's Republic of China; Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), The University of Tokyo , Chiba 277-8583, Japan
- Kohei Inayoshi
- ORCiD
- Kavli Institute for Astronomy and Astrophysics, Peking University , Beijing 100871, People's Republic of China
- Jonathan R. Trump
- ORCiD
- Department of Physics, 196 Auditorium Road, Unit 3046, University of Connecticut , Storrs, CT 06269, USA
- Pablo Arrabal Haro
- ORCiD
- NSF’s National Optical-Infrared Astronomy Research Laboratory , 950 N. Cherry Ave., Tucson, AZ 85719, USA
- Andrea Grazian
- ORCiD
- INAF–Osservatorio Astronomico di Padova , Vicolo dell’Osservatorio 5, I-35122, Padova, Italy
- Mark Dickinson
- ORCiD
- NSF’s National Optical-Infrared Astronomy Research Laboratory , 950 N. Cherry Ave., Tucson, AZ 85719, USA
- Steven L. Finkelstein
- ORCiD
- Department of Astronomy, The University of Texas at Austin , Austin, TX 78712, USA
- Jeyhan S. Kartaltepe
- ORCiD
- Laboratory for Multiwavelength Astrophysics, School of Physics and Astronomy, Rochester Institute of Technology , 84 Lomb Memorial Drive, Rochester, NY 14623, USA
- Michaela Hirschmann
- ORCiD
- Institute of Physics , Laboratory of Galaxy Evolution, Ecole Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290 Versoix, Switzerland
- James Aird
- ORCiD
- Institute for Astronomy, University of Edinburgh , Royal Observatory, Edinburgh EH9 3HJ, UK
- Benne W. Holwerda
- ORCiD
- University of Louisville , Department of Physics and Astronomy, 102 Natural Science Building, Louisville, KY 40292, USA
- Seiji Fujimoto
- ORCiD
- Department of Astronomy, The University of Texas at Austin , Austin, TX 78712, USA; Cosmic Dawn Center (DAWN) , Jagtvej 128, DK-2200 Copenhagen N, Denmark; Niels Bohr Institute, University of Copenhagen , Lyngbyvej 2, DK-2100 Copenhagen Ø, Denmark
- Stéphanie Juneau
- ORCiD
- NSF’s NOIRLab, 950 N. Cherry Ave., Tucson, AZ 85719, USA
- Ricardo O. Amorín
- ORCiD
- Instituto de Investigación Multidisciplinar en Ciencia y Tecnología, Universidad de La Serena , Raul Bitrán 1305, La Serena 2204000, Chile; Departamento de Astronomía, Universidad de La Serena , Av. Juan Cisternas 1200 Norte, La Serena 1720236, Chile
- Bren E. Backhaus
- ORCiD
- Department of Physics, 196 Auditorium Road, Unit 3046, University of Connecticut , Storrs, CT 06269, USA
- Micaela B. Bagley
- ORCiD
- Department of Astronomy, The University of Texas at Austin , Austin, TX 78712, USA
- Guillermo Barro
- ORCiD
- Department of Physics, University of the Pacific , Stockton, CA 90340, USA
- Eric F. Bell
- ORCiD
- Department of Astronomy, University of Michigan , 1085 S. University Ave, Ann Arbor, MI 48109-1107, USA
- Laura Bisigello
- ORCiD
- INAF–Osservatorio Astronomico di Padova , Vicolo dell’Osservatorio 5, I-35122, Padova, Italy; Dipartimento di Fisica e Astronomia “G. Galilei,” Universitá di Padova , Via Marzolo 8, I-35131 Padova, Italy
- Antonello Calabrò
- ORCiD
- Osservatorio Astronomico di Roma , via Frascati 33, Monte Porzio Catone, Italy
- Nikko J. Cleri
- ORCiD
- Department of Physics and Astronomy, Texas A&M University , College Station, TX 77843-4242, USA; George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University , College Station, TX 77843-4242, USA
- M. C. Cooper
- ORCiD
- Department of Physics & Astronomy, University of California , Irvine, 4129 Reines Hall, Irvine, CA 92697, USA
- Xuheng Ding
- ORCiD
- Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), The University of Tokyo , Chiba 277-8583, Japan
- Norman A. Grogin
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Dr., Baltimore, MD 21218, USA
- Luis C. Ho
- ORCiD
- Kavli Institute for Astronomy and Astrophysics, Peking University , Beijing 100871, People's Republic of China; Department of Astronomy, School of Physics, Peking University , Beijing 100871, People's Republic of China
- Taylor A. Hutchison
- ORCiD
- Astrophysics Science Division , NASA Goddard Space Flight Center, 8800 Greenbelt Rd., Greenbelt, MD 20771, USA
- Akio K. Inoue
- ORCiD
- Waseda Research Institute for Science and Engineering, Faculty of Science and Engineering, Waseda University , 3-4-1, Okubo, Shinjuku, Tokyo 169-8555, Japan; Department of Physics, School of Advanced Science and Engineering, Faculty of Science and Engineering, Waseda University , 3-4-1, Okubo, Shinjuku, Tokyo 169-8555, Japan
- Linhua Jiang
- ORCiD
- Kavli Institute for Astronomy and Astrophysics, Peking University , Beijing 100871, People's Republic of China; Department of Astronomy, School of Physics, Peking University , Beijing 100871, People's Republic of China
- Brenda Jones
- Department of Physics and Astronomy, University of Maine , Orono, ME 04469-5709, USA
- Anton M. Koekemoer
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Dr., Baltimore, MD 21218, USA
- Wenxiu Li
- ORCiD
- Kavli Institute for Astronomy and Astrophysics, Peking University , Beijing 100871, People's Republic of China
- Zhengrong Li
- ORCiD
- Kavli Institute for Astronomy and Astrophysics, Peking University , Beijing 100871, People's Republic of China
- Elizabeth J. McGrath
- ORCiD
- Department of Physics and Astronomy, Colby College , Waterville, ME 04901, USA
- Juan Molina
- ORCiD
- Kavli Institute for Astronomy and Astrophysics, Peking University , Beijing 100871, People's Republic of China; Department of Space, Earth and Environment, Chalmers University of Technology , Onsala Space Observatory, SE-439 92 Onsala, Sweden
- Casey Papovich
- ORCiD
- Department of Physics and Astronomy, Texas A&M University , College Station, TX 77843-4242, USA; George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University , College Station, TX 77843-4242, USA
- Pablo G. Pérez-González
- ORCiD
- Centro de Astrobiología (CAB), CSIC-INTA, Ctra. de Ajalvir km 4, Torrejón de Ardoz, E-28850, Madrid, Spain
- Nor Pirzkal
- ORCiD
- ESA/AURA Space Telescope Science Institute , USA
- Stephen M. Wilkins
- ORCiD
- Astronomy Centre, University of Sussex , Falmer, Brighton BN1 9QH, UK; Institute of Space Sciences and Astronomy, University of Malta , Msida MSD 2080, Malta
- Guang Yang
- ORCiD
- Kapteyn Astronomical Institute, University of Groningen , P.O. Box 800, 9700 AV Groningen, The Netherlands; SRON Netherlands Institute for Space Research , Postbus 800, 9700 AV Groningen, The Netherlands
- L. Y. Aaron Yung
- ORCiD
- Astrophysics Science Division , NASA Goddard Space Flight Center, 8800 Greenbelt Rd., Greenbelt, MD 20771, USA
- DOI
- https://doi.org/10.3847/2041-8213/ace5a0
- Journal volume & issue
-
Vol. 954,
no. 1
p. L4
Abstract
We report on the discovery of two low-luminosity, broad-line active galactic nuclei (AGNs) at z > 5 identified using JWST NIRSpec spectroscopy from the Cosmic Evolution Early Release Science (CEERS) survey. We detect broad H α emission in the spectra of both sources, with FWHM of 2060 ± 290 km s ^−1 and 1800 ± 200 km s ^−1 , resulting in virial black hole (BH) masses that are 1–2 dex below those of existing samples of luminous quasars at z > 5. The first source, CEERS 2782 at z = 5.242, is 2–3 dex fainter than known quasars at similar redshifts and was previously identified as a candidate low-luminosity AGN based on its morphology and rest-frame optical spectral energy distribution (SED). We measure a BH mass of M _BH = (1.3 ± 0.4) × 10 ^7 M _⊙ , confirming that this AGN is powered by the least massive BH known in the Universe at the end of cosmic reionization. The second source, CEERS 746 at z = 5.624, is inferred to be a heavily obscured, broad-line AGN caught in a transition phase between a dust-obscured starburst and an unobscured quasar. We estimate its BH mass to be in the range of M _BH ≃ (0.9–4.7) × 10 ^7 M _⊙ , depending on the level of dust obscuration assumed. We perform SED fitting to derive host stellar masses, M _⋆ , allowing us to place constraints on the BH–galaxy mass relationship in the lowest mass range yet probed in the early Universe. The M _BH / M _⋆ ratio for CEERS 2782, in particular, is consistent with or higher than the empirical relationship seen in massive galaxies at z = 0. We examine the narrow emission line ratios of both sources and find that their location on the BPT and OHNO diagrams is consistent with model predictions for moderately low metallicity AGNs with Z / Z _⊙ ≃ 0.2–0.4. The spectroscopic identification of low-luminosity, broad-line AGNs at z > 5 with M _BH ≃ 10 ^7 M _⊙ demonstrates the capability of JWST to push BH masses closer to the range predicted for the BH seed population and provides a unique opportunity to study the early stages of BH–galaxy assembly.
Keywords