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Title:
Rapid X-ray variability in the Seyfert galaxy NGC 6814
Authors:
Tennant, A. F.; Mushotzky, R. F.; Boldt, E. A.; Swank, J. H.
Affiliation:
AA(NASA, Goddard Space Flight Center, Laboratory for High Energy Astrophysics, Greenbelt; Maryland, University, College Park, MD), AB(NASA, Goddard Space Flight Center, Laboratory for High Energy Astrophysics, Greenbelt, MD), AC(NASA, Goddard Space Flight Center, Laboratory for High Energy Astrophysics, Greenbelt, MD), AD(NASA, Goddard Space Flight Center, Laboratory for High Energy Astrophysics, Greenbelt, MD)
Publication:
Astrophysical Journal, Part 1, vol. 251, Dec. 1, 1981, p. 15-25. (ApJ Homepage)
Publication Date:
12/1981
Category:
Astronomy
Origin:
STI
NASA/STI Keywords:
Galactic Nuclei, Light Curve, Seyfert Galaxies, X Ray Sources, X Ray Spectra, Active Galactic Nuclei, Astronomical Catalogs, Autocorrelation, Cross Correlation, Data Reduction, Spectral Correlation, Variability
DOI:
10.1086/159437
Bibliographic Code:
1981ApJ...251...15T

Abstract

In contrast with the Tennant et al (1981) sample of over 30 active galactic nuclei, HEAO 1 A-2 high time resolution X-ray observations of the X-ray emitting Seyfert 1 galaxy NGC 6814 show strong X-ray variability on time scales of less than 3 hr. On a time scale of 90 min, the mean flux varied by a factor of about 2.5, and a characteristic time for variability of 100 + 60 or - 25 sec is obtained by autocorrelation analysis. There is no indication of spectral variability with an upper limit on a change in the power law spectral index of less than about 0.37, for a factor 2 change in intensity. The constraints of such rapid variability on a range of X-ray source mechanisms is discussed.

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