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Cosmic gamma rays — experimental

Published online by Cambridge University Press:  14 August 2015

W. L. Kraushaar
W. L. Kraushaar*
Affiliation:
Department of Physics and Laboratory for Nuclear Science, Massachusetts Institute of Technology Cambridge, Massachusetts, U.S.A.

Abstract

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As yet no experiment, satellite-borne, balloon-borne or earth-based has provided compelling evidence for more than upper limits to the intensity of cosmic gamma rays of more than a few MeV energy. Even these upper limits have been useful in blocking in some of the large scale properties of energetic particles in interstellar and intergalactic space. Nevertheless, the smallest upper limit set on the intensity of diffuse gamma rays 3.10−4 cm−2 s−1 sterad−1 (from the satellite experiment in Explorer XI) is a factor of about 20 above the intensity prediction which can be made with rather good confidence for gamma rays made in cosmic ray collisions with interstellar atomic hydrogen.

Predictions of the gamma ray flux from the various discrete-source emitters of synchrotron radio noise are model-sensitive and in general appreciably smaller than existing upper limits. These upper limits are in the 3.10−4 cm−2 s−1 region for gamma rays of E > 5.107 eV and in the 5.10−11 cm−2 s−1 region for gamma rays of E > 5.1012 eV.

Aucune expérience faite jusqu'à présent sur la Terre ou dans l'espace n'a apporté mieux que des limites supérieures du flux de rayons cosmiques d'énergie supérieure à quelques MeV. Mais ces résultats ont permis d'apporter des limites à certaines caractéristiques des particules énergétiques dans l'espace interstellaire ou intergalactique. La plus faible des limites supérieures trouvées soit 3 10−4 cm−2 s−1 sterad−1 (Explorer XI) est environ 20 fois supérieure aux prévisions basées sur la création de rayons par collisions rayons cosmiques-hydrogène interstellaire. Les prévisions pour les sources radio discrètes émettant du rayonnement synchrotron dépendent beaucoup du modele fournissant des chiffres nettement plus faibles que les limites supérieures existantes qui sont de 3.10−4 cm−2 s−1 pour Ε > 5.107 eu et de 5.10−11 cm−2 s−1 pour Ε > 5 1012 eF.

Резюме

Резюме

Никакой опыт проведенный до сих пор на земле или в пространстве не принес более чем верхние пределы потока космических лучей с энергией превышающей несколько МэВ. Но эти результаты позволили внести ограничения некоторым характеристикам энергетических частиц в пространстве межзвездном или межгалактическом. Самый слабый из найденных верних пределов, т.е. 3.10−4 см−2 сек−1 смер−1 (Эксплорер χΐ) превышает приблизительно в 20/раз предвидения основанные на создании лучей путем соударений космических лучей — межзвездного водорода.

Превидения для дискретных радиоисточников с сихротронным излучением намного зависят от модели, доставляя числа явно более низкие чем существующие верхние пределы, которые равны 3.10−4 см−2 сек−1 для Ε > 5.107 эВ и 5.10−11 см−2 сек−1 для Ε > 5.1012 эВ.

Type
Session V. X and γ Radiation : Stars and Galaxies
Information
Symposium - International Astronomical Union , Volume 23: Astronomical Observations from Space Vehicles , 1965 , pp. 247 - 250
Copyright
Copyright © CNRS 1965 

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