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High energy X-ray observations of extragalactic objectsPreliminary results are reported for scanning observations of the active galaxy NGC 5128 (Cen A) and the Type 1 Seyfert galaxy NGC 4151 with the low-energy detectors of the HEAO-1 A-4 hard X-ray instrument. The X-ray spectra in the energy range from 15 to 100 keV are shown to be consistent with previous observations of these galaxies. It is noted that NGC 5128 rose in intensity from 1972 to 1975, that spectral softening occurred after early 1973, and that the source has since decreased in intensity while maintaining an E to the -1.7 photon power law. The results for NGC 4151 indicate variable absorption below 10 keV and a power-law slope of about E to the -1.4 in the range from 10 keV to 10 MeV.
Document ID
19800029244
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Baity, W. A.
(California Univ. La Jolla, CA, United States)
Gruber, D. E.
(California Univ. La Jolla, CA, United States)
Matteson, J. L.
(California Univ. La Jolla, CA, United States)
Knight, F. K.
(California Univ. La Jolla, CA, United States)
Nolan, P. L.
(California, University La Jolla, Calif., United States)
Scheepmaker, A.
(MIT, Cambridge, Mass.; Leiden, Sterrewacht Leiden, Netherlands)
Wheaton, W. A.
(California Univ. La Jolla, CA, United States)
Hofman, J. A.
(California Univ. La Jolla, CA, United States)
Primini, F. A.
(California Univ. La Jolla, CA, United States)
Lewin, W. H. G.
(MIT Cambridge, Mass., United States)
Date Acquired
August 10, 2013
Publication Date
January 1, 1979
Subject Category
Astrophysics
Meeting Information
Meeting: X-ray astronomy
Location: Innsbruck
Country: Austria
Start Date: May 29, 1978
End Date: June 10, 1978
Accession Number
80A13414
Funding Number(s)
CONTRACT_GRANT: NAS8-27974
Distribution Limits
Public
Copyright
Other

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