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Date and Time of the Query: 2019-08-19 T17:51:53 PDT
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For refcode 1991A&A...250..302P:
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Copyright by European Southern Observatory (ESO). Reproduced by permission
1991A&A...250..302P A statistical analysis of cosmic ray propagation effects on the low frequency radio spectrum of spiral galaxies M.Pohl, Schlickeiser, and E.Hummel Max-Planck-Institut fur Radioastronomie, Auf dem Hugel 69, W-5300 Bonn 1, Federal Republic of Germany Institut fur Astrophysik und extraterrestrische Forschung der Universitat Bonn, Auf dem Hugel 71, W-5300 Bonn 1, Federal Republic of Germany JCMT Unit, Royal Observatory, Blackford Hill, Edinburgh, EH93HJ, Scotland Received February 2, accepted June 27,1991 Abstract. In the last years more and more evidence has emerged for a spectral flattening at low frequencies of the radio continuum emission from normal spiral galaxies. It is the purpose of this paper to calculate theoretical spectra possessing breaks caused by propagation effects of relativistic electrons and to present a statistically significant analysis whether these effects can account for the observed spectra. It is shown that the theoretical spectra change their slope smoothly over a range of at least two decades in frequency. We use the X^2^ and the maximum likelihood method to investigate the spectra of ten galaxies for which data over more than two decades of frequency are available. Six of them evidently have spectral breaks consistent with electron propagation models, three allow no definite decision, and one clearly does not show such features. The sample includes galaxies of different types such as normal galaxies, starbursters and tidally interacting ones. Key words: galaxies - radio continuum - galactic wind - cosmic ray propagation
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