The DEEP2 Galaxy Redshift Survey:: Evolution of close galaxy pairs and major-merger rates up to z∼1.2

We derive the close, kinematic pair fraction and merger rate up to redshift z similar to 1.2 from the initial data of the DEEP2 Redshift Survey. Assuming a mild luminosity evolution, the number of companions per luminous galaxy is found to evolve as (1+z)(m), with m = 0.51 +/- 0.28; assuming no evolution, m = 1.60 +/- 0.29. Our results imply that only 9% of present-day L* galaxies have undergone major mergers since z similar to 1.2 and that the average major merger rate is about 4 x 10(-4) h(3) Mpc(-3) Gyr(-1) for z similar to 0.5-1.2. Most previous studies have yielded higher values.