Fuelling (and quenching) star formation in Brightest Cluster Galaxies

Abstract

We have obtained detailed, spatially-resolved SALT spectroscopy over the entire optical wavelength range for eight nearby, active brightest cluster galaxies (BCGs) in X-ray luminous groups and clusters. This enables us to derive fundamental gas properties such as electron density and gas temperature, which in turn, enables us to derive accurate abundances. Our small, carefully selected, sample consists of BCGs with detected Hα filaments, and have existing data from the X-ray regime available, but lacks the detailed optical emission-line data that will probe the dominant ionisation processes, excitation sources, morphology and kinematics of the hot gas. This, combined with the other multi-wavelength data, will form a complete view of the different phases (hot and cold gas and young stars) and how they interact in the processes of star formation and feedback detected in central galaxies in cooling flow systems, as well as the influence of the surrounding intracluster medium (ICM). Here, we present our first results, illustrating the complexity and spatial variation of the ionisation mechanisms in the nuclei, as well as the large variety of hot gas properties in BCGs.