The dependence of the average spectral index of extragalactic sources on luminosity in complete samples selected at different frequencies is shown to vary in a manner that directly reflects their evolutionary properties. In particular, easily recognizable features are introduced by a luminosity dependent evolution and by the presence of a cutoff in the redshift distribution. The expected dependence on luminosity of the average optical to X-ray energy index αox for X-ray selected active galactic nuclei is discussed in some detail.

Differential Information on the Evolution of Extragalactic Sources from Spectral Index Distributions

Danese, Luigi;
1984

Abstract

The dependence of the average spectral index of extragalactic sources on luminosity in complete samples selected at different frequencies is shown to vary in a manner that directly reflects their evolutionary properties. In particular, easily recognizable features are introduced by a luminosity dependent evolution and by the presence of a cutoff in the redshift distribution. The expected dependence on luminosity of the average optical to X-ray energy index αox for X-ray selected active galactic nuclei is discussed in some detail.
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http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1984A%26A...131L...1D&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf
Danese, Luigi; Dezotti, G.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/15816
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