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Spectral Index - Redshift Relation for Radio Galaxies and Quasars

Published online by Cambridge University Press:  25 May 2016

R.D. Dagkesamanskii
R.D. Dagkesamanskii*
Affiliation:
Astrospace Center of P.N. Lebedev Physics Institute of RAS Moscow Leniskii prospekt 53 Russia

Extract

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Cosmological evolution of synchrotron spectra of the powerful extragalactic radio sources was studied by many authors. Some indications of such an evolution had been found firstly by analysis of ‘spectral index - flux density’ (α – S) relation for the sample of relatively strong radio sources. Later Gopal-Krishna and Steppe extended the analysis to weaker sources and found that the slope of αmed (S) curve changes dramatically at intermediate flux densities. Gopal-Krishna and Steppe pointed out that the maxima of the αmed (S) curve and of differential source counts are at almost the same flux density ranges (see, Fig. 2). It has to be noticed that the all mentioned results were obtained using the low-frequency spectral indices and on the basis of low frequency samples.

Type
Cosmological Implications
Information
Symposium - International Astronomical Union , Volume 175: Extragalactic Radio Sources , 1996 , pp. 569 - 570
Copyright
Copyright © Kluwer 1996 

References

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