Morphological Transformation and Star Formation Quenching of Massive
  Galaxies at 0.5 < z < 2.5 in 3D-HST/CANDELS
  To figure out the effect of stellar mass and local environment on
morphological transformation and star formation quenching in galaxies, we use
the massive ($M_* \geq 10^{10} M_{\odot}$) galaxies at $0.5 \leq z \leq 2.5$ in
five fields of 3D-HST/CANDELS. Based on the {\it UVJ} diagnosis and the
possibility of possessing spheroid, our sample of massive galaxies are
classified into four populations: quiescent early-type galaxies (qEs),
quiescent late-type galaxies (qLs), star-forming early-type galaxies (sEs), and
star-forming late-type galaxies (sLs). It is found that the quiescent fraction
is significantly elevated at the high ends of mass and local environmental
overdensity, which suggests a clear dependence of quenching on both mass and
local environment. Over cosmic time, the mass dependence of galaxy quiescence
decreases while the local environment dependence increases. The early-type
fraction is found to be larger only at high-mass end, indicating a evident mass
dependence of morphological transformation. This mass dependence becomes more
significant at lower redshifts. Among the four populations, the fraction of
active galactic nucleus (AGN) in the qLs peaks at $2<z \leq 2.5$, and rapidly
declines with cosmic time. The sEs are found to have higher AGN fractions of
$20-30\%$ at $0.5\leq z<2$ . The redshift evolution of AGN fractions in the qLs
and sEs suggests that the AGN feedback could have played important roles in the
formation of the qLs and sEs.
