WINGS-SPE III: Equivalent width measurements, spectral properties and
  evolution of local cluster galaxies
  [Abridged] We investigate the frequency of the various spectral types as a
function both of the clusters' properties and of the galaxies' characteristics.
In this way, using the same classification criteria adopted for higher redshift
studies, we can consistently compare the properties of the local cluster
population to those of their more distant counterparts. We describe a method we
have developed to automatically measure the equivalent width of spectral lines
in a robust way even in spectra with a non optimal signal to noise. Like this,
we can derive a spectral classification reflecting the stellar content, based
on the presence and strength of the [OII] and Hdelta lines. We are able to
measure 4381 of the ~6000 originally observed spectra, in the fields of 48
clusters, 2744 of which are spectroscopically confirmed cluster members. The
spectral classification is then analyzed as a function of galaxies' luminosity,
stellar mass, morphology, local density and host cluster's global properties,
and compared to higher redshift samples (MORPHS and EDisCS). The vast majority
of galaxies in the local clusters population are passive objects, being also
the most luminous and massive. At a magnitude limit of Mv<-18, galaxies in a
post-starburst phase represent only ~11% of the cluster population and this
fraction is reduced to ~5% at Mv<-19.5, which compares to the 18% at the same
magnitude limit for high-z clusters. "Normal" star forming galaxies [e( c )]
are proportionally more common in local clusters. The relative occurrence of
post--starbursts suggests a very similar quenching efficiency in clusters at
redshifts in the 0 to ~1 range. Furthermore, more important than the global
environment, the local density seems to be the main driver of galaxy evolution
in local clusters, at least with respect to their stellar populations content.
