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The absence of rapid X-ray variability in active galaxiesVariations on time scales ranging from minutes to several hours in the X-ray flux from 54 observations of 38 active galaxies are identified. The sample is composed mostly of Seyfert I galaxies but also includes radio galaxies, NELG's BL Lacs and 3C 273. Only NGC 6814 varied on time scales as short as 100 sec. No other source was observed to vary with a time scale of less than 12 hours. Large amplitude short term variations are not a characteristic of the X-ray emission from active galaxies. Upper limits on sigma sub I/I ranged from 2% for Cen A, 5% for NGC 4151, to approximately 20% for sources giving 1 ct/sec in the detector. Three objects NGC 3227, NGC 4151 and MCG 5-23-16 show variability consistent with a time scale of approximately 1 day. Ways to reconcile the rapid variability seen for NGC 6814 (and NGC 4051) with the general stability observed for the other objects are considered.
Document ID
19820022328
Acquisition Source
Legacy CDMS
Document Type
Thesis/Dissertation
Authors
Tennant, A. F. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Mushotzky, R. F. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
September 4, 2013
Publication Date
June 1, 1982
Subject Category
Astrophysics
Report/Patent Number
NAS 1.15:83966
NASA-TM-83966
Accession Number
82N30204
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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