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Measuring the 511 keV emission in the direction of 1E1740.7-2942 with BATSEObservations of the 511 keV emission in the direction of 1E 1740.7-2942 (1E) using the earth burst and transient source experiment (BATSE) onboard the Compton Gamma Ray Observatory (CGRO), are presented. The CGRO phase 1 average spectrum of 1E is calculated using a method which assumes that a given source spectrum is the sum of the flux coming directly from the object and the contribution from the surrounding diffuse emission. The 1E light curve is calculated in the 40 to 150 keV range. It presents a constant flux excess of 70 mCrab in comparison with observations from the SIGMA gamma ray telescope onboard the GRANAT observatory. By removing this contribution, the 1E spectral transition from the low state to the high standard state observed by SIGMA is confirmed, and it is shown that the 511 keV flux is independent of the 1E long term evolution from low state to high standard state. It is concluded that the 511 keV emission of (4.2 +/- 1.3) x 140(exp -4) photons/sq cm s observed in the direction of 1E is mainly diffuse and spatially extended.
Document ID
19970025743
Acquisition Source
Jet Propulsion Laboratory
Document Type
Conference Paper
Authors
Wallyn, P.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Ling, J. C.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Mahoney, W. A.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Wheaton, W. A.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Durouchoux, P.
(Commissariat a l'Energie Atomique Saclay France)
Corbel, S.
(Commissariat a l'Energie Atomique Saclay France)
Astier-Perret, L.
(Ecole Polytechnique Palaiseau France)
Poirot, L.
(Ecole Polytechnique Palaiseau France)
Date Acquired
August 17, 2013
Publication Date
March 1, 1997
Publication Information
Publication: Proceedings of 2nd INTEGRAL Workshop 'The Transparent Universe'
Subject Category
Astronomy
Accession Number
97N25213
Funding Number(s)
CONTRACT_GRANT: NAS7-100
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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