Understanding the transformation of spirals to lenticulars
  By studying the individual star-formation histories of the bulges and discs
of lenticular (S0) galaxies, it is possible to build up a sequence of events
that leads to the cessation of star formation and the consequent transformation
from the progenitor spiral. In order to separate the bulge and disc stellar
populations, we spectroscopically decomposed long-slit spectra of Virgo Cluster
S0s into bulge and disc components. Analysis of the decomposed spectra shows
that the most recent star formation activity in these galaxies occurred within
the bulge regions, having been fuelled by residual gas from the disc. These
results point towards a scenario where the star formation in the discs of
spiral galaxies are quenched, followed by a final episode of star formation in
the central regions from the gas that has been funnelled inwards through the
disc.
