Double galaxy redshifts and dynamical analyses. II. Sample comparisons

Current analyses of magnitude and center-of-mass velocity data for samples of binary galaxies cannot easily provide an adequate estimate of the mass within the orbit and are unlikely ever to furnish useful information on the mass-to-light ratios of galaxies. This is shown by a comparison of different data sets for the same physical systems. Detailed analysis of individual pairs seems to be the only way that double galaxies can provide dynamically determined masses. As a secondary result, the comparison, together with analysis of data of higher quality than usual, suggests that the claimed periodicity is not a physical property of the actual galaxy pairs. 29 refs