Quenching vs. Quiescence: forming realistic massive ellipticals with a
  simple starvation model
  The decrease in star formation (SF) and the morphological change necessary to
produce the $z=0$ elliptical galaxy population are commonly ascribed to a
sudden quenching event, which is able to rid the central galaxy of its cold gas
reservoir in a short time. Following this event, the galaxy is able to prevent
further SF and stay quiescent via a maintenance mode. We test whether such a
quenching event is truly necessary using a simple model of quiescence. In this
model, hot gas (all gas above a temperature threshold) in a $\sim10^{12}
M_{\odot}$ halo mass galaxy at redshift $z\sim3$ is prevented from cooling. The
cool gas continues to form stars at a decreasing rate and the galaxy stellar
mass, morphology, velocity dispersion and position on the color magnitude
diagram (CMD) proceed to evolve. By $z=0$, the halo mass has grown to $10^{13}
M_{\odot}$ and the galaxy has attained characteristics typical of an observed
$z=0$ elliptical galaxy. Our model is run in the framework of a cosmological,
smooth particle hydrodynamic code which includes SF, early stellar feedback,
supernova feedback, metal cooling and metal diffusion. Additionally, we
post-process our simulations with a radiative transfer code to create a mock
CMD. In contrast to previous assumptions that a pure "fade away" model evolves
too slowly to account for the sparsity of galaxies in the "green valley", we
demonstrate crossing times of $<$1 Gyr. We conclude that no sudden quenching
event is necessary to produce such rapid colour transitions.
