Timing the evolution of quiescent and star-forming local galaxies
  Constraining the star formation histories (SFHs) of individual galaxies is
crucial to understanding the mechanisms that regulate their evolution. Here, we
combine multi-wavelength (ultraviolet, optical, and infrared) measurements of a
very large sample of galaxies (~230,000) at z<0.16, with physically motivated
models of galaxy spectral energy distributions to extract constraints on galaxy
physical parameters (such as stellar mass and star formation rate) as well as
individual SFHs. In particular, we set constraints on the timescales in which
galaxies form a certain percentage of their total stellar mass (namely, 10, 50
and 90%). The large statistics allows us to average such measurements over
different populations of galaxies (quiescent and star-forming) and in narrow
ranges of stellar mass. As in the downsizing scenario, we confirm that low-mass
galaxies have more extended SFHs than high-mass galaxies. We also find that at
the same observed stellar mass, galaxies that are now quiescent evolve more
rapidly than galaxies that are currently still forming stars. This suggests
that stellar mass is not the only driver of galaxy evolution, but plays along
with other factors such as merger events and other environmental effects.
