Hubble Space Telescope STIS Ultraviolet Spectral Evidence of Outflow in Extreme Narrow-Line Seyfert 1 Galaxies. II. Modeling and Interpretation
Abstract
We present modeling to explore the conditions of the broad-line-emitting gas in two extreme narrow-line Seyfert 1 galaxies, using the observational results described in the first paper of this series. Photoionization modeling using CLOUDY was conducted for the broad blueshifted wind lines and the narrow, symmetric, rest-wavelength-centered disk lines separately. A broad range of physical conditions was explored for the wind component, and a figure of merit was used to quantitatively evaluate the simulation results. Of the three minima in the figure-of-merit parameter space, we favor the solution characterized by an X-ray-weak continuum, elevated abundances, a small column density (logNH~21.4), a relatively high ionization parameter (logU~-1.2 to -0.2), a wide range of densities (logn~7-11), and a covering fraction of ~0.15. The presence of low-ionization emission lines implies that the disk component is optically thick to the continuum, and the Si III]/C III] ratio implies a density of 1010-1010.25 cm-3. A low ionization parameter (logU=-3) is inferred for the intermediate-ionization lines, unless the continuum is ``filtered'' through the wind before illuminating the intermediate-line-emitting gas, in which case logU=-2.1. The location of the emission regions was inferred from the photoionization modeling and a simple ``toy'' dynamical model. A large black hole mass (1.3×108 Msolar) radiating at 11% of the Eddington luminosity is consistent with the kinematics of both the disk and wind lines, and an emission radius of ~104 RS is inferred for both. We compare these results with previous work and discuss implications.
Based on observations made with the NASA ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. These observations are associated with proposal 7360. Based on observations obtained at the Cerro Tololo Inter-American Observatory, a division of the National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.- Publication:
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The Astrophysical Journal
- Pub Date:
- August 2004
- DOI:
- 10.1086/422089
- arXiv:
- arXiv:astro-ph/0402452
- Bibcode:
- 2004ApJ...611..125L
- Keywords:
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- Galaxies: Seyfert;
- Galaxies: Quasars: Emission Lines;
- Galaxies: Quasars: Individual: Alphanumeric: IRAS 13224-3809;
- Galaxies: Quasars: Individual: Alphanumeric: 1H 0707-495;
- Ultraviolet: Galaxies;
- Astrophysics
- E-Print:
- 45 pages, 15 figures (4 color), accepted for publication in ApJ, abstract shortened