1995/06/12 by Erick J. Guerra, Guerra, Erick J., Ruth A. Daly +1
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9506078
8 pages, 6 figures in text, uuencoded compressed postscript file. To appear in the proceedings of the Cygnus A Workshop
arxiv created 1995/06/12 · arxiv updated 2009/12/01
Powerful extended radio galaxies like Cygnus A can be used for cosmological tests. The characteristic, time-independent length D_* for several radio sources is calculated and compared to the average physical length for a sample of radio galaxies. The ratio of these two lengths as a function of redshift is used to constrain cosmological parameters. Cygnus A is the only low-redshift (z<0.5) radio galaxy for which we have an estimate for D_*. We comment on the sensitivity to this one low-redshift point, and results including and excluding Cygnus A are shown. A low density universe is favored, and the one free model parameter is relatively well constrained.