Imaging Spectroscopy of Ionized Gaseous Nebulae around Optically Faint AGNs at Redshift z ∼ 2
Abstract
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 ({ \mathcal R } = 20-25 ν {L}ν ∼ {10}44-{10}46 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 {km} {{{s}}}-1), 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.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 2018
- DOI:
- 10.3847/1538-4357/aae156
- arXiv:
- arXiv:1809.04089
- Bibcode:
- 2018ApJ...866..119L
- Keywords:
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- galaxies: active;
- galaxies: fundamental parameters;
- galaxies: high-redshift;
- galaxies: structure;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 33 pages, 18 figures. Accepted for publication in ApJ