Abstract
view Abstract Citations (6) References (20) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The broad component of hydrogen emission lines in nuclei of Seyfert galaxies: comments on a charge exchange model. Katz, A. Abstract A model to account for the broad hydrogen line emission from the nuclei of Seyfert galaxies based on charge exchange and collisional processes, as proposed by Ptak and Stoner, is investigated. The model consists of a source of fast (E 10' eV) protons streaming through a medium of quiescent gas. One of the major problems that results from such a model concerns the strong narrow hydrogen line core that would be produced, in direct conflict with the observations. The lines cannot arise from gas arranged throughout a spherical volume surrounding the source of the fast particles because the fast protons would produce far more ionizations than the possible number of recombinations. A very dense shell source of less than 1 AU in thickness and at least several tens of parsecs in radius must be invoked to reproduce the asymmetric broad profiles observed. There must be absorption throughout the center of the shell to account for the line profiles. The gas cannot be arranged in dense clumps throughout a large volume because momentum exchange of the gas with the primary particles would quickly accelerate any clumps. The energy balance and energy requirements of such a model are investigated, and it is found that an energy equal to or greater than the total luminosity of most Seyfert galaxies is required to produce the hydrogen lines alone. The gas must be mostly neutral and dense (N 10 ) if a reasonable temperature is to be maintained. Subject headings: atomic and molecular processes - galactic nuclei - Seyfert galaxies Publication: The Astrophysical Journal Pub Date: June 1975 DOI: 10.1086/153602 Bibcode: 1975ApJ...198..255K Keywords: Charge Exchange; Emission Spectra; Galactic Nuclei; H Lines; Hydrogen; Seyfert Galaxies; Astronomical Models; Gas Density; Photons; Proton Irradiation; Spectral Line Width; Astrophysics full text sources ADS | data products NED (1)
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