Abstract
ASSUMING that the red-shifts of quasars are cosmological, Longair1, and Roeder and Mitchell2, have suggested that the present available distribution of flux-densities at 178 Mc/s, S178, of quasars against red-shift implies that the radio luminosity, P, of quasars which exist at cosmic epoch t is a decreasing function of t. This would be an important conclusion for cosmology, because the natural inference is that the anomalous steep radio source counts are also due to this evolution in luminosity, rather than to any variation in the spatial density of sources. This conclusion seems premature, however, because the present available data for quasars can also be interpreted as the result of a decrease in the source density with t.
Similar content being viewed by others
References
Longair, M. S., Nature, 211, 949 (1966).
Roeder, R. C., and Mitchell, G. F., Nature, 212, 165 (1966).
Davidson, W., Mon. Not. Roy. Astro. Soc., 124, 79 (1962).
Longair, M. S., Mon. Not. Roy. Astro. Soc., 133, 421 (1966).
Kellerman, K., Astrophys. J., 140, 969 (1964).
Pauliny-Toth, I. I. K., Wade, C. M., and Heeschen, D. S., Astrophys. J., Suppl. 13, 65 (1966).
Sandage, A. R., Astrophys. J., 141, 1560 (1965).
Sandage, A. R., Veron, P., and Wyndham, J. D., Astrophys. J., 142, 1307 (1965).
Burbidge, M., Hoyle, F., and Lynds, C. R., Nature, 210, 774 (1966).
Rees, M., and Sciama, D. W., Nature, 211, 1283 (1966).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
ROWAN-ROBINSON, M. Density Evolution Hypothesis for Quasars. Nature 212, 1556–1557 (1966). https://doi.org/10.1038/2121556a0
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1038/2121556a0
- Springer Nature Limited
This article is cited by
-
Bulletin GRG, No. 25: List of publications
General Relativity and Gravitation (1971)
-
Radio Galaxies as Cosmological Probes
Nature (1967)