Expanding Quasars and the Expansion of the Universe
The μ–z diagram (Figure 1) plots the observed internal proper motion μ versus redshift z for 32 extragalactic radio sources associated with active galactic nuclei. The observed points fall below an upper bound which decreases with redshift; there is a statistically significant anticorrelation between redshift and internal proper motion.
Additional Information© 1988 by the IAU. An earlier version of this work was published by Cohen 1987, in Superluminal Radio Sources, ed. Zensus and Pearson (Cambridge: Cambridge University Press).