A Caltech Library Service

Interpretation of Source Counts and Redshift Data in Evolutionary Universes

Wall, J. V. and Pearson, T. J. and Longair, M. S. (1977) Interpretation of Source Counts and Redshift Data in Evolutionary Universes. In: Radio Astronomy and Cosmology. IAU Symposium Proceedings Series. No.74. D. Reidel , Dordrecht, pp. 269-277. ISBN 9789401012607.

[img] PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


Conventional interpretation of the N(S) relation requires cosmic evolution of the radio source population. Investigators agree on the general features of this evolution: it must be confined to the most luminous sources, and must be strong, the numbers of such sources at redshifts of 1 to 4 exceeding the present numbers by a factor ≳103. There is no consensus as to whether density or luminosity evolution prevails (or both), whether a cutoff in redshift is necessary, or whether the source populations found in high-frequency surveys follow even the general evolutionary picture deduced for the low-frequency survey population. It is therefore hardly surprising that the physical basis of the evolution, the ultimate goal of N(S) interpretation, remains largely “in the realm of imaginative speculation” (P. A. G. Scheuer).

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Pearson, T. J.0000-0001-5213-6231
Additional Information:© 1977 by the IAU.
Series Name:IAU Symposium Proceedings Series
Issue or Number:74
Record Number:CaltechAUTHORS:20181119-131749664
Persistent URL:
Official Citation:Wall, J., Pearson, T., & Longair, M. (1977). Interpretation of Source Counts and Redshift Data in Evolutionary Universes. Symposium - International Astronomical Union, 74, 269-277. doi:10.1017/S0074180900016247
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:91025
Deposited By: Tony Diaz
Deposited On:19 Nov 2018 21:43
Last Modified:16 Nov 2021 03:37

Repository Staff Only: item control page