The role of major gas-rich mergers on the evolution of galaxies from the
  blue cloud to the red sequence
  With the aim of exploring the fast evolutionary path from the blue cloud of
star-forming galaxies to the red sequence of quiescent galaxies in the local
universe, we select a local advanced merging infrared luminous and
ultraluminous galaxy (adv-merger (U)LIRGs) sample and perform careful dust
extinction corrections to investigate their positions in the SFR-$M_{\ast}$,
u-r and NUV-r color-mass diagrams. The sample consists of 89 (U)LIRGs at the
late merger stage, obtained from cross-correlating the IRAS Point Source
Catalog Redshift Survey and 1 Jy ULIRGs samples with the Sloan Digital Sky
Survey DR7 database. Our results show that $74\%\pm 5\%$ of adv-merger (U)LIRGs
are localized above the $1\, \sigma$ line of the local star-forming galaxy main
sequence. We also find that all adv-merger (U)LIRGs are more massive than and
as blue as the blue cloud galaxies after corrections of Galactic and internal
dust extinctions, with $95\%\pm 2\%$ and $81\%\pm 4\%$ of them outside the blue
cloud on the u-r and NUV-r color-mass diagrams, respectively. These results,
combined with the short timescale for exhausting the molecular gas reservoir in
adv-merger (U)LIRGs ($3\times 10^{7}$ to $3\times 10^{8}$ years), imply that
the adv-merger (U)LIRGs are likely at the starting point of the fast
evolutionary track previously proposed by several groups. While the number
density of adv-merger (U)LIRGs is only $\sim 0.1\%$ of the blue cloud
star-forming galaxies in the local universe, this evolutionary track may play a
more important role at high redshift.
