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Size and structure of the narrow-line region of quasars
The Astrophysical Journal
  • Nicola Bennert, Ruhr-Universitat Bochum
  • Heino Falcke, Max-Planck Institut für Radioastronomie
  • Hartmut Schulz, Ruhr-Universitat Bochum
  • Andrew S. Wilson, University of Maryland - College Park
  • Beverley J. Wills, University of Texas at Austin
Publication Date

We have observed the narrow-line regions (NLRs) of the seven brightest radio-quiet Palomar-Green (or Bright Quasar Survey) quasars (z < 0.5) with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope (HST). Linear-ramp filters were used to image the [O III] λ5007 line emission with 00455-01 pixel resolution. We find that the NLRs are very compact with typical extents of 2''-4''. Two quasars show compact filamentary structures similar to Seyfert NLRs. They may be related to radio outflows. Most interestingly, when including a sample of Seyfert galaxies observed with HST, we tentatively find that the size of the NLR is proportional to the square root of the [O III] luminosity. This is comparable to the scaling found for the size of the broad-line region with continuum luminosity, which has been interpreted in terms of a constant photoionization parameter. The relation determined here connects the NLR of radio-quiet quasars and Seyfert galaxies over 3 orders of magnitude in [O III] luminosity.

Citation Information
Nicola Bennert, Heino Falcke, Hartmut Schulz, Andrew S. Wilson, et al.. "Size and structure of the narrow-line region of quasars" The Astrophysical Journal Vol. 574 Iss. 2 (2002) p. L105 - L109
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