Imaging Spectroscopy of Ionized Gaseous Nebulae around Optically Faint AGNs at Redshift z ∼ 2

David R. Law, Charles C. Steidel, Yuguang Chen, Allison L. Strom, Gwen C. Rudie, Ryan F. Trainor

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


We present Keck/OSIRIS laser guide-star assisted adaptive optics (LGSAO) integral-field spectroscopy of [O iii] λ5007 nebular emission from 12 galaxies hosting optically faint ( = 20-25; erg s-1) active galactic nuclei (AGNs) at redshift z ∼ 2-3. In combination with deep Hubble Space Telescope Wide Field Camera 3 (HST/WFC3) rest-frame optical imaging, Keck/MOSFIRE rest-optical spectroscopy, and Keck/KCWI rest-UV integral-field spectroscopy, we demonstrate that both the continuum and emission-line structures of these sources exhibit a wide range of morphologies, from compact, isolated point sources to double-AGN merging systems with extensive ∼50 kpc tidal tails. One of the 12 galaxies previously known to exhibit a proximate damped Lyα system coincident in redshift with the galaxy shows evidence for both an extended [O iii] narrow-line emission region and spatially offset Lyα emission (with morphologically distinct blueshifted and redshifted components) indicative of large-scale gas flows photoionized by the central AGN. We do not find widespread evidence of star formation in the host galaxies surrounding these AGNs; the [O iii] velocity dispersions tend to be high (σ = 100-500 ), the continuum morphologies are much more compact than a mass-matched star-forming comparison sample, and the diagnostic nebular emission-line ratios are dominated by an AGN-like ionizing spectrum. The sample is most consistent with a population of AGNs that radiate at approximately their Eddington limit and photoionize extended [O iii] nebulae whose characteristic sizes scale approximately as the square root of the AGN luminosity.

Original languageEnglish (US)
Article number119
JournalAstrophysical Journal
Issue number2
StatePublished - Oct 20 2018


  • galaxies: active
  • galaxies: fundamental parameters
  • galaxies: high-redshift
  • galaxies: structure

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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