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Amplitude Variations in Pulsed Radio Sources

  • P. A. G. Scheuer

Abstract

The radio pulses from the sources discovered by Hewish et al.1,2 show extremely regular repetition rates but quite erratic amplitude fluctuations, over time scales ranging from less than a second1 to hours3 or even days1. The rapid pulse-to-pulse variations appear to be well correlated on different frequencies3, and, as will be shown, they are most probably an intrinsic property of the source. The long-period variations show little, if any, correlation between different frequencies3, and it seems difficult to imagine a source of wide-band pulses which have a very complex spectrum that is preserved over hundreds or thousands of pulses. Such complex frequency structure rather suggests that the emission process is modulated by interference phenomena, either between a number of coherent pulsed sources on the surface of a star, or else between a number of images of the source caused by irregular refraction in an interstellar medium. The latter possibility is considered in this article.

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References

  1. 1.
    Hewish, A., Bell, S. J., Pilkington, J. D. H., Scott, P. F., and Collins, R. A., Nature, 217, 709 (1968), (Paper 1).ADSCrossRefGoogle Scholar
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    Pilkington, J. D. H., Hewish, A., Bell, S. J., and Cole, T. W., Nature, 218, 126 (1968), (Paper 2).ADSCrossRefGoogle Scholar
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    Lyne, A. G., and Rickett, B. J., Nature, 218, 326 (1968), (Paper 10).ADSCrossRefGoogle Scholar
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    Uscinski, B. J., Phil. Trans. Roy. Soc., A, 262, 609 (1968).ADSCrossRefGoogle Scholar
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    Scott, P. F., and Collins, R. A., Nature, 218, 230 (1968), (Paper 8).ADSCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1968

Authors and Affiliations

  • P. A. G. Scheuer
    • 1
  1. 1.Mullard Radio Astronomy Observatory, Cavendish LaboratoryUniversity of CambridgeUK

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