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Title: Gemini long-slit observations of luminous obscured quasars: Further evidence for an upper limit on the size of the narrow-line region

We examine the spatial extent of the narrow-line regions (NLRs) of a sample of 30 luminous obscured quasars at 0.4 < z < 0.7 observed with spatially resolved Gemini-N GMOS long-slit spectroscopy. Using the [O III] λ5007 emission feature, we estimate the size of the NLR using a cosmology-independent measurement: the radius where the surface brightness falls to 10{sup –15} erg s{sup –1} cm{sup –2} arcsec{sup –2}. We then explore the effects of atmospheric seeing on NLR size measurements and conclude that direct measurements of the NLR size from observed profiles are too large by 0.1-0.2 dex on average, as compared to measurements made to best-fit Sérsic or Voigt profiles convolved with the seeing. These data, which span a full order of magnitude in IR luminosity (log (L {sub 8} {sub μm}/erg s{sup –1}) = 44.4-45.4), also provide strong evidence that there is a flattening of the relationship between NLR size and active galactic nucleus luminosity at a seeing-corrected size of ∼7 kpc. The objects in this sample have high luminosities which place them in a previously under-explored portion of the size-luminosity relationship. These results support the existence of a maximal size of the NLR around luminous quasars; beyond thismore » size, there is either not enough gas or the gas is over-ionized and does not produce enough [O III] λ5007 emission.« less
Authors:
;  [1] ;  [2] ;  [3] ; ;  [4] ;  [5]
  1. Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States)
  2. Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)
  3. Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States)
  4. Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218 (United States)
  5. Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)
Publication Date:
OSTI Identifier:
22356830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 787; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BRIGHTNESS; COMPARATIVE EVALUATIONS; COSMOLOGY; EMISSION; EVOLUTION; GALAXIES; GALAXY NUCLEI; LUMINOSITY; QUASARS; SPECTROSCOPY; SURFACES