Characterization of Omega-WINGS galaxy clusters. I. Stellar light and mass profiles

TL;DR

This study derives luminosity and stellar mass profiles for 46 nearby galaxy clusters from the Omega-WINGS survey, revealing non-homologous structures and a cluster color-magnitude relation similar to that of galaxies, challenging current formation models.

Contribution

It provides the first measurement of a color-magnitude relation for galaxy clusters and compares cluster scaling relations with those of early-type galaxies, highlighting similarities in their growth.

Findings

Galaxy clusters are non-homologous structures.

A cluster color-magnitude relation similar to galaxies is observed.

Clusters exhibit growth patterns akin to those of early-type galaxies.

Abstract

Galaxy clusters are the largest virialized structures in the observable Universe. The knowledge of their properties provides many useful astrophysical and cosmological information. Our aim is to derive the luminosity and stellar mass profiles of the nearby galaxy clusters of the Omega-WINGS survey and to study the main scaling relations valid for such systems. We have merged the data of the WINGS and Omega-WINGS databases, sorted the sources according to the distance from the brightest cluster galaxy (BCG) and calculated the integrated luminosity profiles in the $B$ and $V$ bands, taking into account extinction, photometric and spatial completeness, K-correction and background contribution. Then, by exploiting the spectroscopic sample we derived the stellar mass profiles of the clusters. We got the luminosity profiles of 46 galaxy clusters, reaching $r_{200}$ in 30 cases, and the stellar mass profiles of 42 of our objects. We successfully fitted all the integrated luminosity growth profiles with one or two embedded S\'ersic components, deriving the main clusters parameters. Finally, we checked the main scaling relation among the clusters parameters in comparison with those obtained for a selected sample of early-type galaxies (ETGs) of the same clusters. We found that the nearby galaxy clusters are non-homologous structures like ETGs and exhibit a color-magnitude (CM) red-sequence relation very similar to that observed for galaxies in clusters. These properties are not expected in the current cluster formation scenarios. In particular the existence of a CM relation for clusters, shown here for the first time, suggests that the baryonic structures grow and evolve in a similar way at all scales.