2007/05/16 by J. S. Kartaltepe, Jeyhan S. Kartaltepe, D. B. Sanders +16 · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Astronomy and Astrophysical Research #Atmospheric Ozone and Climate #Galaxies: Formation, Evolution, Phenomena #Gamma-ray bursts and supernovae #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/519953
22 pages including 4 figures and 2 tables. Accepted for publication in the ApJS COSMOS special issue. For the high resolution version of figure 4, see: http://www.ifa.hawaii.edu/~jeyhan/pairs/
arxiv created 2007/05/16 · openalex publication_date 2007/05/16 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We measure the fraction of luminous galaxies in pairs at projected separations of 5-20 kpc out to z=1.2 in the COSMOS field using ACS images and photometric redshifts derived from an extensive multiwavelength dataset. Analysis of a complete sample of 106,188 galaxies more luminous than MV=-19.8 (~ LV*) in the redshift range 0.1 < z < 1.2 yields 1,749 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 (SDSS). 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 to 3.