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 z ~ 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 ~ 1. 2 and that the average major merger rate is about 4* 10^-4 h^3 Mpc^-3 Gyr^-1 for z ~ 0. 5 - 1. 2. Most previous studies have yielded higher values.