  In this paper, we present a sample of cluster galaxies devoted to study the
environmental influence on the star-formation activity. This sample of galaxies
inhabits in clusters showing a rich variety in their characteristics and have
been observed by the SDSS-DR6 down to M_B ~ -18 and by the GALEX AIS throughout
sky regions corresponding to several megaparsecs. We assign the broad-band and
emission-line fluxes from ultraviolet to far-infrared to each galaxy performing
an accurate spectral energy distribution for spectral fitting analysis. The
clusters follow the general X-ray luminosity vs. velocity dispersion trend of
L_X/sigma_c^4.4. The analysis of the distributions of galaxy density counting
up to the 5th nearest neighbor Sigma_5 shows: (1) the virial regions and the
cluster outskirts share a common range in the high density part of the
distribution. This can be attributed to the presence of massive galaxy
structures in the surroundings of virial regions (2) The virial regions of
massive clusters (sigma_c>550 km s^-1) present a Sigma_5 distribution
statistically distinguishable (~96%) from the corresponding distribution of
lowmass clusters (sigma_c<550 km s^-1). Both massive and low-mass clusters
follow a similar density-radius trend, but the low-mass clusters avoid the high
density extreme. We illustrate, with Abell 1185, the environmental trends of
galaxy populations. Maps of sky projected galaxy density show how
low-luminosity star-forming galaxies appear distributed along more spread
structures than their giant counterparts, whereas low-luminosity passive
galaxies avoid the low-density environment. Giant passive and star-forming
galaxies share rather similar sky regions with passive galaxies exhibiting more
concentrated distributions.
