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The formation of emission lines in quasars and Seyfert nucleiThe photoionization and heating throughout a quasar emission-line cloud optically thick at the Lyman edge are calculated. Photoionization and collisional ionization from excited states of hydrogen are included, which maintain a substantial electron fraction after the exhaustion of Lyman continuum photons halts ground-state photoionization. Observed values are explained for Ly-alpha/H-beta, H-alpha/H-beta, P-alpha/H-alpha, He I 5876/H-beta, O I 8446/H-alpha, and Mg II 2798/H-beta. The dependence of line strengths on physical conditions is discussed, and plotting Fe II/4570/H-beta versus Balmer continuum/H-beta is suggested. Other observations are also suggested, and the degree of asymmetry is given between the forward and backward emission of lines from a finite slab to make possible the use of comparative line profile studies to elucidate cloud kinematics.
Document ID
19820032821
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Kwan, J.
(Bell Telephone Laboratories, Inc. Murray Hill, NJ, United States)
Krolik, J. H.
(MIT Cambridge, MA, United States)
Date Acquired
August 10, 2013
Publication Date
November 15, 1981
Publication Information
Publication: Astrophysical Journal
Subject Category
Astrophysics
Accession Number
82A16356
Funding Number(s)
CONTRACT_GRANT: NSG-7643
Distribution Limits
Public
Copyright
Other

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