Abstract
An analysis is given here of the flux of cosmic γ rays of energy above 100 MeV from the directions of 13 local molecular clouds. We show that only in a few clouds does the cosmic ray intensity need to exceed the value near the Earth to explain the γ-ray fluxes. Possible reasons for the few excesses are considered. Our conclusion is important because some of the enigmatic γ-ray ‘sources’ are identified; furthermore, γ-ray data can be coupled with knowledge about the distribution of gas in the Galaxy to throw light on the problem ‘where do cosmic rays come from?’.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Issa, M. R., Strong, A. W. & Wolfendale, A. W. J. Phys. G: Nucl. Phys. 7, 565 (1981).
Blitz, L. in Giant Molecular Clouds in the Galaxy (eds Solomon, P. M. & Edmunds, M. G.) 1 (Pergamon, Oxford, 1980).
Blitz, L. & Shu, F. H. Astrophys. J. 238, 148 (1980).
Dickman, R. L. Astrophys. J. Suppl. 37, 407 (1978).
Sivan, J. P. Astr. Astrophys. Suppl. 16, 163 (1974).
Elias, J. H. Astrophys. J. 224, 857 (1978).
Baud, B. & Wouterloot, J. G. Astr. Astrophys. 90, 297 (1980).
Elmegreen, B. G. & Lada, C. J. Astr. J. 81, 1089 (1976).
Elemgreen, B. G., Lada, C. J. & Dickinson, D. F. Astrophys. J. 230, 415 (1979).
Dickel, H. R. Astr. Astrophys. 31, 11 (1974).
Wolfendale, A. W. IUPAP/IAU Symp. No. 94, 309.
Myers, P. C., Ho, P. T. P. & Schneps, M. H. Astrophys. J. 220, 864 (1978).
Grasdalen, G. L., Strom, K. M. & Strom, S. E. Astrophys. J. Lett. 184, L53 (1973).
Paul, J. A., Cassé, M. & Montmerle, T. IUPAP/IAU Symp. No. 94, 325
Vrba, F. J. Astr. J. 82, 198 (1977).
Baart, E. E., de Jager, G. & Mountfort, P. I. (in the press).
Fichtel, C. E. et al. NASA Tech. Mem. 79656 (GSFC, Greenbelt, 1978).
Thompson, D. J., Fichtel, C. E., Hartman, R. C., Kniffen, D. A. & Lamb, R. C. NASA Tech.Mem. X-662-76-198 (GSFC, Greenbelt, 1976).
Wills, R. D. et al. Non-solar Gamma Rays (COSPAR) (eds Cowsik, R. & Wills, R. D.) 43 (Pergamon, Oxford, 1980).
Mayer-Hasselwander, H. A. et al. Ann. N.Y. Acad. Sci. 336, 211 (1980).
Hermsen, W. thesis, Univ. Leiden (1980).
Caraveo, P. A. et al. Astr. Astrophys. 91, L3 (1980).
Li, T. P. & Wolfendale, A. W. Astr. Astrophys. (in the press).
Cassé, M. & Paul, J. A. Astrophys. J. 237, 236 (1980).
Montmerle, T. Astrophys. J. 231, 95 (1979).
Montmerle, T. Phil. Trans. R. Soc. (in the press).
Issa, M. R., Riley, P. L., Strong, A. W. & Wolfendale, A. W. Nature 287, 810 (1980).
Reynolds, R. J. Astrophys. J. 203, 151 (1976).
Brandt, J. C., Stecher, T. P., Crawford, D. L. & Maran, S. P. Astrophys. J. Lett. 163, L99 (1971).
Rossano, G. S. Astr. J. 83, 234 (1978).
Turner, D. G. & Moffat, A. F. J. Mon. Not. R. astr. Soc. 192, 283 (1980).
Bertiaud, F. C. Astrophys. J. 128, 533 (1958).
Whittet, D. C. B. Mon. Not. R. astr. Soc. 168, 371 (1974).
Protheroe, R. J., Strong, A. W. & Wolfendale, A. W. Mon. Not. R. astr. Soc. 188, 863 (1979).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Issa, M., Wolfendale, A. γ Rays from the cosmic ray irradiation of local molecular clouds. Nature 292, 430–433 (1981). https://doi.org/10.1038/292430a0
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/292430a0
- Springer Nature Limited
This article is cited by
-
Low-energy cosmic rays: regulators of the dense interstellar medium
The Astronomy and Astrophysics Review (2022)
-
Lightning black holes as unidentified TeV sources
Journal of Astrophysics and Astronomy (2018)
-
Gamma rays from molecular clouds
Astrophysics and Space Science (2007)
-
Cosmic rays in the galaxy (Review)
Radiophysics and Quantum Electronics (1987)