Global Properties of the Rich Cluster ABCG 209 at z~0.2. Spectroscopic and Photometric Catalogue

TL;DR

This study provides a comprehensive analysis of the global properties, dynamics, and galaxy populations of the rich cluster ABCG 209 at z~0.2, revealing ongoing merging activity and insights into galaxy evolution.

Contribution

It offers new spectroscopic and photometric data, detailed dynamical analysis, and explores the photometric relations and stellar populations of cluster galaxies.

Findings

ABCG 209 is undergoing strong dynamical evolution with merging subclumps.

Cluster early-type galaxies follow a consistent Kormendy relation across wavelengths.

Chemical evolution influences the intrinsic scatter of the photometric plane.

Abstract

This paper is aimed at giving an overview of the global properties of the rich cluster of galaxies ABCG 209. This is achieved by complementing the already available data with new medium resolution spectroscopy and NIR photometry which allow us to i) analyse in detail the cluster dynamics, distinguishing among galaxies belonging to different substructures and deriving their individual velocity distributions, using a total sample of 148 galaxies in the cluster region, of which 134 belonging to the cluster; ii) derive the cluster NIR luminosity function; iii) study the Kormendy relation and the photometric plane of cluster early-type galaxies (ETGs). Finally we provide an extensive photometric (optical and NIR) and spectroscopic dataset for such a complex system to be used in further analyses investigating the nature, formation and evolution of rich clusters of galaxies. The observational scenario confirms that ABCG 209 is presently undergoing strong dynamical evolution with the merging of two or more subclumps. This interpretation is also supported by the detection of a radio halo (Giovannini et al. 2006) suggesting that there is a recent or ongoing merging. Cluster ETGs follow a Kormendy relation whose slope is consistent with previous studies both at optical and NIR wavelengths. We investigate the origin of the intrinsic scatter of the photometric plane due to trends of stellar populations, using line indices as indicators of age, metallicity and alpha/Fe enhancement. We find that the chemical evolution of galaxies could be responsible for the intrinsic dispersion of the Photometric Plane.