A cosmological test with compact radio sources

Abstract

The recent proposal by Kellermann (1993) to use the angular size/redshift relation of compact radio sources to obtain information on the value of cosmological parameters has provoked considerable discussion in the astronomical community. I present here a careful re-analysis of the angular size/redshift data of radio jets used by Kellermann (1993), using a Kolmogorov-Smirnov test to check the independence of the distribution of linear jet sizes from redshift under the assumption that no evolution is present in the sources. The test takes into account biasing of the sample due to the limited resolution. While the data are compatible with an Einstein-de~Sitter Universe ($P=0.2$), they are not sufficient to rule out a significant part of the $(Ω_0,λ_0)$-plane.