We revisit the evolution of galaxy morphology in the COSMOS field over the
redshift range 0.2β€zβ€1, using a large and complete sample of 33,605
galaxies with a stellar mass of log(Mββ/Mββ)>9.5 with
significantly improved redshifts and comprehensive non-parametric morphological
parameters. Our sample has 13,881 (βΌ41.3%) galaxies with reliable
spectroscopic redshifts and has more accurate photometric redshifts with a
ΟNMADββΌ0.005. This paper is the first in a series that
investigates merging galaxies and their properties. We identify 3,594 major
merging galaxies through visual inspection and find 1,737 massive galaxy pairs
with log(Mββ/Mββ)>10.1. Among the family of non-parametric
morphological parameters including C, A, S, Gini, M20β, AOβ, and DOβ, we find that the outer asymmetry parameter AOβ
and the second-order momentum parameter M20β are the best tracers of
merging features than other combinations. Hence, we propose a criterion for
selecting candidates of violently star-forming mergers: M20β>β3AOβ+3 at 0.2β6AOβ+3.7 at 0.6<z<1.0.
Furthermore, we show that both the visual merger sample and the pair sample
exhibit a similar evolution in the merger rate at z<1, with ββΌ(1+z)1.79Β±0.13 for the visual merger sample and ββΌ(1+z)2.02Β±0.42 for the pair sample. The visual merger sample has a
specific star formation rate that is about 0.16\,dex higher than that of
non-merger galaxies, whereas no significant star formation excess is observed
in the pair sample. This suggests that the effects of mergers on star formation
differ at different merger stages.Comment: 21 pages, 12 figures; accepted for publication in Ap