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Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. IV - Intensity variations of the optical emission lines of NGC 5548Measurements of optical emission-line flux variations based on spectra of the Seyfert galaxy NGC 5548 obtained between December 1988 and October 1989 are reported. All of the measured optical emission lines, H-alpha, H-beta, H-gamma, He I 5876, and He II 4686, exhibit the same qualitative behavior as the UV and optical continua, but with short time delays, or lags, which are different for the various lines. Cross-correlation analysis is applied to measure the lags between the various lines and the continuum. Similar lags are found with respect to the UV continuum for H-alpha and H-beta, 17 and 19 d, respectively. The lag for H-gamma is shorter (13 d), only somewhat larger than the lag measured for Ly-alpha (about 10 d). The helium lines respond to continuum variations more rapidly than the hydrogen lines, with lags of about 7 d for He II 4686 and 11 d for He I 5876.
Document ID
19930052386
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Dietrich, M.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Kollatschny, W.
(Goettingen, Univ.-Sternwarte Germany)
Peterson, B. M.
(Ohio State Univ. Columbus, United States)
Bechtold, J.
(Steward Observatory Tucson, AZ, United States)
Bertram, R.
(Ohio State Univ. Columbus; Lowell Observatory, Flagstaff, AZ, United States)
Bochkarev, N. G.
(State Astronomical Inst. Moscow, Russia)
Boroson, T. A.
(Kitt Peak National Observatory Tucson, AZ, United States)
Carone, T. E.
(Steward Observatory, Tucson, AZ; California Univ. Berkeley, United States)
Elvis, M.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Filippenko, A. V.
(California Univ. Berkeley, United States)
Date Acquired
August 16, 2013
Publication Date
May 10, 1993
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 408
Issue: 2
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
93A36383
Funding Number(s)
CONTRACT_GRANT: NSF AST-86-14510
CONTRACT_GRANT: NSF AST-87-14937
CONTRACT_GRANT: NSF AST-89-15258
CONTRACT_GRANT: NSF AST-89-57063
CONTRACT_GRANT: NAG5-13660
CONTRACT_GRANT: NSF AST-90-58510
CONTRACT_GRANT: NAS5-29293
CONTRACT_GRANT: BMFT-FKZ-05-5GO42A1
CONTRACT_GRANT: NAS8-30751
CONTRACT_GRANT: NSF RII-88-00600
Distribution Limits
Public
Copyright
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