Search for H alpha emitters in Galaxy Clusters with Tunable Filters
  The studies of the evolution of galaxies in Galaxy Clusters have as a
traditional complication the difficulty in establishing cluster membership of
those sources detected in the field of view. The determination of spectroscopic
redshifts involves long exposure times when it is needed to reach the cluster
peripherical regions of/or clusters at moderately large redshifts, while
photometric redshifts often present uncertainties too large to offer
significant conclusions. The mapping of the cluster of galaxies with narrow
band tunable filters makes it possible to reach large redshifts intervals with
an accuracy high enough to establish the source membership of those presenting
emission/absorption lines easily identifiable, as H alpha. Moreover, the
wavelength scan can include other lines as [NII], [OIII] or $H_{\beta}$
allowing to distinguish those sources with strong stellar formation activity
and those with an active galactic nuclei. All this makes it possible to
estimate the stellar formation rate of the galaxies observed. This, together
with ancillary data in other wavelengths may lead to a good estimation of the
stellar formation histories. It will shed new light over the galaxy evolution
in clusters and will improve our understanding of galaxy evolution, especially
in the outer cluster regions, usually less studied and with significant
unexploited data that can not be correctly interpreted without redshift
determination.
