Evolution of the Frequency of Luminous (\geq L_V*) Close Galaxy Pairs at z < 1.2 in the COSMOS Field
arXiv:0705.2266 · doi:10.1086/519953
Abstract
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 M_V=-19.8 (~ L_V*) 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 \propto (1+z)^{n=3.1 \pm 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.
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/
References in corpus (7)
- The Cosmic Evolution Survey (COSMOS) -- Overview
- Weak Gravitational Lensing with COSMOS: Galaxy Selection and Shape Measurements
- The Cosmic Evolution Survey (COSMOS): Subaru Observations of the HST COSMOS Field
- Large Structures and Galaxy Evolution in COSMOS at z < 1.1
- Photometric Redshifts of Galaxies in COSMOS
- Hubble Space Telescope H-Band Imaging Survey of Massive Gas-Rich Mergers
- Near Infrared Adaptive Optics Imaging of QSO Host Galaxies