Key points are not available for this paper at this time.
The statistics of galaxy pairs and the merging fraction are examined in a magnitude-limited sample of galaxies with redshift measurements. The sample has a magnitude limit of r = 21. 5 mag and an average redshift of 0. 38. The fraction of galaxies in physical close pairs with projected separation less than 20 h^-1^ kpc is estimated to be ~15%. About 60% of these pairs are physically within 20 h^-1^ kpc of each other and represent the most likely merging population. Using statistics from UGC galaxies as representative of the current epoch, the close pair fraction is estimated to evolve as (1 + z) ⁴. 0+/-1. 5^, in general agreement with previous investigations based solely on direct images. Separating the galaxies into subsamples according to redshift produces essentially identical results. The average g - r colors and luminosities of paired and isolated galaxies are found to be nearly identical, with only suggestive differences. However, as up to 2/3 of the paired galaxies may be optical pairs or physical pairs that are not merging, this lack of difference between paired and isolated galaxies may be attributed to contamination.
Yee et al. (Mon,) studied this question.