Evolution of the frequency of luminous (≥L* v) close galaxy pairs at z < 1.2 in the COSMOS field

J. S. Kartaltepe, D. B. Sanders, N. Z. Scoville, D. Calzetti, P. Capak, A. Koekemoer, B. Mobasher, T. Murayama, M. Salvato, S. S. Sasaki, Y. Taniguchi

Research output: Contribution to journalArticlepeer-review

131 Citations (Scopus)

Abstract

We measure the fraction of luminous galaxies in pairs at projected separations of 5-20 kpc out to z = 1.2 in the Cosmic Evolution Survey (COSMOS) field using ACS images and photometric redshifts derived from an extensive multiwavelength data set. Analysis of a complete sample of 106,188 galaxies more luminous than My = -1.9.8 (∼L* V) in the redshift range 0.1 < z < 1.2 yields 1749 galaxy pairs. These data are supplemented by a local (z = 0-0.1)value for the galaxy pair fraction derived from the Sloan Digital Sky Survey. After statistically correcting the COSMOS pair sample for chance line-of-sight superpositions, the evolution in the pair fraction is fit by a power law ∝(1 + z) n=3.1*0.1. If this strongly evolving pair fraction continues out to higher redshift, ∼50% of all luminous galaxies at z ∼ 2 are in close pairs. This clearly signifies that galaxy mergers are a very significant and possibly dominant mechanism for galaxy evolution during the epoch of galaxy formation at z = 1-3.

Original languageEnglish
Pages (from-to)320-328
Number of pages9
JournalAstrophysical Journal, Supplement Series
Volume172
Issue number1
DOIs
Publication statusPublished - 2007

Keywords

  • Cosmology: observations
  • Galaxies: evolution galaxies: formation
  • Galaxies: interactions large-scale structure of universe
  • Surveys

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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