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Upper limits to the flux of high energy γ-rays from selected quasi-stellar and other sources, using the Cerenkov technique

Published online by Cambridge University Press:  14 August 2015

C. D. Long
Affiliation:
University College Dublin, Eire
N. A. Porter
Affiliation:
University College Dublin, Eire
T. C. Weekes
Affiliation:
University College Dublin, Eire
J. F. Fruin
Affiliation:
Atomic Energy Research Establishment, Harwell, United Kingdom
J. V. Jelley
Affiliation:
Atomic Energy Research Establishment, Harwell, United Kingdom

Abstract

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Upper flux limits at the earth for γ rays of energy greater than about 5 × 1012 eV, have been established for the quasi-stellar sources 3C 147, 3C 196, 3C 273, the Crab Nebula, and the magnetic variable 53 Cam. They are all of the order 10-10 photons cm-2. s-1. Corresponding upper energy limits at emission are of the order 5 × 1047 ergs s-1 for the quasi-stellar sources, and 5 × 1035 ergs s-1 for the Crab Nebula, if γ-ray absorption is assumed negligible. Possible absorption mechanisms are discussed.

On a calculé une limite supérieure du flux de rayons γ d'énergie supérieure à 5 1012eV reçu sur la Terre et provenant des sources quasi-stellaires 3C 147, 3C 196, 3C 273, de la Nébuleuse du Grabe et de la variable magnétique 53 Cam. On trouve dans tous les cas un flux de l'ordre de 10−10 photons cm−2 s−1. Les limites supérieures de l'énergie émise par la source sont de 5 χ 1047 ergs s−1 pour les sources quasi-stellaires, et 5 χ 1035 ergs s−1 pour la Nébuleuse du Crabe, si l'on suppose l'absorption négligeable. On discute certains mécanismes d'absorption.

Резюме

Резюме

Вычислен верхний предел потока лучей γ с энергией превышающей 5.10 12эВ, полученный на Земле и происходящий из квази-звездных источников Зс 147, Зс 196, Зс 273, из туманности Краба и из магнитной переменной 53 Сам. Во всех случаях найден поток порядка 1011 фотонов/ см2 сек. Верхние пределы излученной источником энергии — 5 χ 1047 эрг/сек для источншов квази- эвездных, и 5 χ 1035 эрг/сек для Краба, если предположить поглощение пренебрежимым. Обсуждены некоторые механизмы поглощения.

Type
Session V. X and γ Radiation : Stars and Galaxies
Copyright
Copyright © CNRS 1965 

References

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