Hidden Little Monsters: Spectroscopic Identification of Low-mass, Broad-line AGNs at z > 5 with CEERS

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…

• NA
  National Aeronautics and Space Administration

  Awards: 5-03127, ERS-01345, NAS 5-03127
• ST
  Space Telescope Science Institute

  Awards: JWST-AR-02446, 5-03127, JWST-ERS-01345, NAS 5-03127
• NN
  National Natural Science Foundation of China

  Awards: CMS-CSST-2021-A06, 11950410493, 12073003, 10.13039, 11991052, AEI/10.13039/501100011033, 12150410307, 11721303, 12003003, CMS-CSST-2021-A04
• MD
  Ministero dell’Istruzione, dell’Università e della Ricerca

  Award: PGC2018-093499-B-I00
• MD
  Ministerio de Ciencia e Innovación

  Awards: B-I00, 10.13039, PGC2018-093499-B-I00, AEI/10.13039/501100011033, PGC2018, 501100011033, AEI/10, 10.13039/501100011033, 13039/501100011033
• UO
  University of California Observatories
• SA
  Science and Technology Facilities Council

  Award: ST/X001040/1
• AE
  Agencia Estatal de Investigación

  Awards: AEI/10.13039/501100011033, 501100011033, 10.13039/501100011033, 13039, 10.13039, AEI/10, 13039/501100011033, AEI/10., PGC2018-093499-B-I00