On the interdependence of galaxy morphology, star formation, and
  environment in massive galaxies in the nearby Universe
  Using multi-wavelength data, from UV-optical-near-mid IR, for $\sim$6000
galaxies in the local Universe, we study the dependence of star formation on
the morphological T-types for massive galaxies ($\log M_*/M_\odot \geq 10$). We
find that, early-type spirals (Sa-Sbc) and S0s predominate in the green valley,
which is a transition zone between the star forming and quenched regions.
Within the early-type spirals, as we move from Sa to Sbc spirals the fraction
of green valley and quenched galaxies decreases, indicating the important role
of the bulge in the quenching of galaxies. The fraction of early-type spirals
decreases as we enter the green valley from the blue cloud, which coincides
with the increase in the fraction of S0s. This points towards the morphological
transformation of early-type spiral galaxies into S0s which can happen due to
environmental effects such as ram-pressure stripping, galaxy harassment, or
tidal interactions. We also find a second population of S0s which are actively
star-forming and are present in all environments. Since morphological T-type,
specific star formation rate (sSFR), and environmental density are all
correlated with each other, we compute the partial correlation coefficient for
each pair of parameters while keeping the third parameter as a control
variable. We find that morphology most strongly correlates with sSFR,
independent of the environment, while the other two correlations
(morphology-density and sSFR-environment) are weaker. Thus, we conclude that,
for massive galaxies in the local Universe, the physical processes that shape
their morphology are also the ones that determine their star-forming state.
