UV to Far-IR catalog of a galaxy sample in nearby clusters: spectral energy distributions and environmental trends.
HERNANDEZ-FERNANDEZ J.D., IGLESIAS-PARAMO J. and VILCHEZ J.M.
Abstract (from CDS):
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 MB∼ -18, and by the Galaxy Evolution Explorer AIS throughout sky regions corresponding to several megaparsecs. We assign the broadband 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 versus velocity dispersion trend of LX∝ σ4.4c. The analysis of the distributions of galaxy density counting up to the 5th nearest neighbor Σ5shows: (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 (σc > 550 km/s) present a Σ5 distribution statistically distinguishable (∼96%) from the corresponding distribution of low-mass clusters (σ_ c_< 550 km/s). 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.