Browsing by Author "CARLBERG, RG"

Now showing 1 - 1 of 1
  • No Thumbnail Available
    Item
    A SURVEY OF FAINT GALAXY PAIRS
    (1994) CARLBERG, RG; PRITCHET, CJ; INFANTE, L
    A sample of faint, V-magnitude selected, galaxy pairs, having physical separations less than similar to 20 h(-1) kpc, is used to examine the rise in the merger rate with redshift and the statistical relations between close pairs and the field galaxy population. Redshifts have been obtained for a subset of 14 galaxies (V less than or equal to 22.5) that are in close (theta < 6'') pairs, along with a comparison sample of 38 field galaxies. Two-color photometry is available for 378 galaxies in the same fields. The average redshift of the V less than or equal to 22.5 field population is 0.36, statistically equal to the average redshift of 0.42 for the pairs. The similarity of the two redshift distributions, Delta z less than or equal to 0.1, limits any differential luminosity enhancement of close pairs to less than half a magnitude. The pairs are somewhat bluer than the field and have nearly twice the average [O Pi] detection rate of the field, but the differences are not statistically significant. The field population has an angular correlation at separations of theta less than or equal to 6'' higher than the inward extrapolation of omega(theta) proportional to theta(-0.8), which may be a population of ''companions'' not present at the current epoch, or, luminosity enhancement of intrinsically faint galaxies in pairs. Physical pairs closer than 20 h(-1) kpc comprise similar to 10% of the faint galaxies in our survey fields. The same physical separation applied to local galaxies finds only 4.6% in pairs. If the rise in close, low relative velocity pairs with redshift is parameterized as (1 + z)(m), then m = 3.4 +/- 1.0. If all the pairs merge, then the average galaxy mass would be about 32% smaller at z = 0.4 than locally.