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Upper limits to the annihilation radiation luminosity of Centaurus AA high resolution observation of the active nucleus galaxy Centaurus A (NGC 5128) was made by the GSFC low energy gamma-ray spectrometer (LEGS) during a balloon flight on 1981 November 19. The measured spectrum between 70 and 500 keV is well represented by a power law of the form 1.05 x 10 (-4) (E/100 keV) (-1.59) ph/sq cm/s with no breaks or line features observed. The 98 percent confidence (2 sigma) flux upper limit for a narrow (3 keV) 511-keV positron annihilation line is 9.9 x 10 (-4) ph/sq cm/s. Using this upper limit, the ratio of the narrow-line annihilation radiation luminosity to the integral or = 511 keV luminosity is estimated to be 0.09 (2 sigma upper limit). This is compared with the measured value for our Galactic center in the Fall of 1979 of 0.10 to 0.13, indicating a difference in the emission regions in the nuclei of the two galaxies.
Document ID
19850049155
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Gehrels, N.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Cline, T. L.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Paciesas, W. S.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Teegarden, B. J.
(NASA Goddard Space Flight Center Greenbelt; Maryland, University, College Park, MD; Alabama, University, Huntsville, AL, United States)
Tueller, J.
(NASA Goddard Space Flight Center Greenbelt; Maryland, University, College Park MD, United States)
Dirouchoux, P.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Hameury, J. M.
(Commissariat a l'Energie Atomique, Centre d'Etudes Nucleaires de Saclay, Gif-sur-Yvette Essonne, France)
Date Acquired
August 12, 2013
Publication Date
January 1, 1983
Subject Category
Astrophysics
Meeting Information
Meeting: Positron-electron pairs in astrophysics
Location: Greenbelt, MD
Start Date: January 6, 1983
End Date: January 8, 1983
Accession Number
85A31306
Distribution Limits
Public
Copyright
Other

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