Counting Pairs of Faint Galaxies

Abstract

view Abstract Citations (48) References (32) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Counting Pairs of Faint Galaxies Woods, David ; Fahlman, Gregory G. ; Richer, Harvey B. Abstract The number of close pairs of galaxies observed to faint magnitude limits, when compared to nearby samples, determines the interaction or merger rate as a function of redshift The prevalence of mergers at intermediate redshifts is fundamental to understanding how galaxies evolve and the relative population of galaxy types. Mergers have been used to explain the excess of galaxies in faint blue counts above the numbers expected from no-evolution models. Using deep CFHT (I ≤ 24) imaging of a "blank" field, we find a pair fraction which is consistent with the galaxies in our sample being randomly distributed with no significant excess of "physical" close pairs. This is contrary to the pair fraction of 34%±9% found by Burkey et al. for similar magnitude limits and using an identical approach to the pair analysis. Various reasons for this discrepancy are discussed. Colors and morphologies of our close pairs are consistent with the bulk of them being random superpositions although, as indicators of interaction, these criteria are uncertain as a result of contamination of field galaxies and difficulty in seeing structure at intermediate redshifts, respectively. This observed lack of close pairs is probably linked with the decreasing amplitude of the angular correlation function at faint limits. If our faint samples are comprised of galaxies which have a higher average redshift than brighter samples studied by other workers, then either the merger rate has been overestimated or there is a change in its behavior from what is observed at brighter magnitude limits. Publication: The Astrophysical Journal Pub Date: November 1995 DOI: 10.1086/176461 arXiv: arXiv:astro-ph/9506053 Bibcode: 1995ApJ...454...32W Keywords: GALAXIES: CLUSTERS: GENERAL; GALAXIES: INTERACTIONS; Astrophysics E-Print: 471 kb uuencoded, postscript file with figures included, 32 pages, To appear in the Nov., 1995 issue of Astrophysical Journal full text sources arXiv | ADS | data products SIMBAD (2)