DO RELATIVISTIC ELECTRONS EITHER GAIN OR LOSE ENERGY, OUTSIDE OF EXTRAGALACTIC NUCLEI

In the generally accepted models of high-luminosity extragalactic radi o sources, the relativistic electron distribution evolves significantl y outside of its source in the galactic nucleus; synchrotron losses oc cur throughout the source, and the harder (flatter) spectra seen in th e hot spots are one indicator of relativistic particle acceleration. O ur reanalysis and interpretation of the Carilli et al. (1991) data on Cygnus A, on the other hand, showed no evidence for evolution of the e lectron distribution function, and no evidence of the universally assu med injection power-law distribution. Having found a spectrum that des cribes an entire source, we have also introduced the technique of corr ecting synchrotron maps for frequency-dependent effects. In this way, a partial deconvolution of the underlying physical parameters is possi ble. In Cygnus A, this correction procedure led to the dominance of a hitherto unrecognized structure, an edge-brightened channel girdled by rings. We briefly discuss some implications of this work and our plan s to continue this line of investigation.