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Author Thompson, K. L.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ QUASARS ♦ EMISSION SPECTRA ♦ BALMER LINES ♦ HELIUM ♦ LINE WIDTHS ♦ MATHEMATICAL MODELS ♦ PHOTOIONIZATION ♦ RADIATION TRANSPORT ♦ RED SHIFT ♦ SODIUM ♦ ALKALI METALS ♦ COSMIC RADIO SOURCES ♦ ELEMENTS ♦ FLUIDS ♦ GASES ♦ IONIZATION ♦ METALS ♦ NONMETALS ♦ RARE GASES ♦ SPECTRA ♦ Astrophysics & Cosmology- Stars & Quasi-Stellar, Radio & X-Ray Sources
Abstract For six QSOs, the H-alpha profile was fit to the position of He I 5876 A and Na I 5890, 5896 doublet. The implied Na I/H-alpha ratio ranged between 0.004 and 0.042. Photoionization models were run with a variety of parameters, including density, column density, ionization parameter, two different incident spectra, and either constant density or constant gas pressure. The models use zone results from Ferland's code Cloudy and solved for the sodium emission. The set of cloud parameters that can produce approximately the observed Na I/H-alpha ratios consist of only the high-density clouds, with n(H) about 10 to the 11th/cu cm and only at column densities N(H) = 10 exp 23.5/sq cm or more. The highest Na I/H-alpha ratios are found in models where the sodium is shielded. The large range of observed Na I/H-alpha ratios implies a corresponding range of cloud conditions. 23 refs.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 1991-06-01
Publisher Place United States
Journal Astrophysical Journal
Volume Number 374


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