Abstract
Recent observations1 with the Exosat X-ray satellite have confirmed the existence of an apparently diffuse galactic ridge of emission extending over the inner Galaxy (l = 320° −40°) and confined to about ±2° in galactic latitude. On the basis of measurements2 carried out in the galactic plane at l≃55°, we have proposed previously3 that the diffuse galactic X-ray flux known at that time could be understood in terms of the synchrotron radiation of cosmic-ray electrons in the galactic magnetic field. The more extensive Exosat measurements fit nicely into this picture and the X-ray-producing electrons can now be readily understood as being secondary to the ultra-high-energy protons, which are themselves generated in galactic objects as epitomized by the recently discovered4,5 Cygnus X-3. We show here that, on this model, the number of Cyg X-3-like objects present in the Galaxy at any one time, averaged over the past 103 yr or so, is ≃30.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Warwick, R.S., Turner, M.J.L., Watson, M.G. & Willingale, R. Nature 317, 218–221 (1985).
Protheroe, R.J., Wolfendale, A.W. & Wdowczyk, J. Mon. Not. R. astr. Soc. 192, 445–454 (1980).
Schwartz, D.A. in COSPAR: X–Ray Astronomy (eds Baity, W. A. & Peterson, L. E.) (Pergamon, Oxford, 1979).
Samorski, M. & Stamm, W. Astrophys. J. Lett. 268, L17–L21 (1983).
Lloyd–Evans, J. et al. Nature 305, 784–787 (1983).
Cooke, B.A., Griffiths, R.E. & Pounds, K.A. Nature 224, 134–137 (1969).
Kearsey, S., Osborne, J.L. & Phillips, S. IAU Symp. 94, 223–224 (1981).
Protheroe, R.J. & Wolfendale, A.W. Astr. Astrophys. 84, 128–134 (1980).
Eichler, D. & Vestrand, W.T. Nature 307, 613–614 (1984).
Hillas, A.M. Nature, 312, 50–51 (1984).
Issa, M.R., Riley, P.A., Strong, A.W. & Wolfendale, A.W. Astr. Astrophys. 141, 394–400 (1984).
Rana, N.C., Sadzinska, M., Wdowczyk, J. & Wolfendale, A.W. Astr. Astrophys. 141, 394–401 (1984).
Bhat, C.L., Sapru, M.L. & Razdan, H. Astrophys. J. (submitted).
Protheroe, R.J. & Clay, R.W. Nature 315, 205–207 (1985).
Wdowczyk, J. & Wolfendale, A.W. Nature 305, 609–610 (1984).
Linsley, J. Proc. 18th int. Conf. Cosmic Rays 12, 135–191 (1983).
Bhat, C.L., Kifune, T. & Wolfendale, A.W. Astr. Astrophys. (in the press).
Dzikowski, T., Gawin, J., Grochalska, B., Korejwo, J. & Wdowczyk, J. Proc. 19th int. Conf. Cosmic Rays Vol. 1,238–241 (1985).
Alien, C.W. Astrophysical Quantities (Athlone, London, 1973).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bhat, C., Kifune, T. & Wolfendale, A. A cosmic-ray explanation of the galactic ridge of cosmic X-rays. Nature 318, 267–269 (1985). https://doi.org/10.1038/318267a0
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/318267a0
- Springer Nature Limited