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Evidence for Large Scale Cosmic Ray Electron Gradients in the Galaxy

Published online by Cambridge University Press:  25 April 2016

W. R. Webber
W. R. Webber*
Affiliation:
Department of Physics, University of Tasmania
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Extract

In recent years observations of γ-ray emission from the disk of the galaxy have provided a new opportunity for research into the structure of the spiral arms of our own galaxy. In Figure 1 we show a map of the structure of the disk of the galaxy as observed for γ-rays of energy > 100 MeV by the SAS-2 satellite (Fichtel et al. 1975). The angular resolution of these measurements is ~ 3°, and besides two point sources at l = 190° and 265° several features related to the spiral structure of the galaxy are evident in the data. Most of these γ-rays are believed to arise from the decay of π° mesons produced by the nuclear interactions of cosmic rays (mostly protons) with the ambient interstellar gas. As a result, the γ-ray fluxes represent a measure of the line of sight integral of the product of the cosmic ray density NCR and the interstellar matter density N1

Type
Invited Papers
Information
Publications of the Astronomical Society of Australia , Volume 3 , Issue 1 , September 1976 , pp. 1 - 6
Copyright
Copyright © Astronomical Society of Australia 1976

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