The distribution of cosmic rays in the Galaxy and their dynamics as deduced from recent gamma-ray observations.
Abstract
Data from SAS-2 on the galactic gamma ray line flux as a function of longitude is examined. It is shown that the gamma ray emissivity varies with galactocentric distance and is about an order of magnitude higher than the local value in a toroidal region between 4 and 5 kpc from the galactic center. This enhancement is accounted for in part by first-order Fermi acceleration, compression, and trapping of cosmic rays consistent with present ideas of galactic dynamics and galactic structure theory. Calculations indicate that cosmic rays in the 4 to 5 kpc region are trapped and accelerated over a mean time of the order of a few million years or about 2 to 4 times the assumed trapping time in the solar region of the galaxy on the assumption that only an increased cosmic ray flux is responsible for the observed emission. Cosmic ray nucleons, cosmic ray electrons, and ionized hydrogen gas were found to have a strikingly similar distribution in the galaxy according to both the observational data and the theoretical model discussed.
- Publication:
-
The Context and Status of Gamma-Ray Astronomy
- Pub Date:
- November 1974
- Bibcode:
- 1974csgr.conf..241P
- Keywords:
-
- Cosmic Rays;
- Galactic Radiation;
- Gamma Rays;
- Radiation Distribution;
- Emission Spectra;
- Flux Density;
- Galactic Structure;
- Hydrogen;
- Interstellar Gas;
- Nucleons;
- Radiation Sources;
- Radio Emission;
- Sas;
- Satellite Observation;
- Space Radiation