Letter | Published:

Spectral Variations of the Structure of the Radio Sources Cassiopeia A and Cygnus A

Naturevolume 207pages740741 (1965) | Download Citation



IN a recent article, Ryle, Elsmore and Neville1 gave a beautiful synthesis of the brightness distributions associated with the radiation at 1,400 Mc/s from the radio sources Cygnus A and Cassiopeia A. No discussion was given in their article of the relevance of earlier observations at other frequencies. A comparison of the results of Ryle et al. with the original low frequency measurements highlights some interesting features of both sources and stresses the need for further measurements at even lower frequencies.

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  1. Department of Physics, University of Manchester

    • R. C. JENNISON


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