Title: Stellar populations in the centres of brightest cluster galaxies

Author(s): S.I. Loubser, P. Sanchez-Blazquez, A. Sansom, I.K. Soechting

Abstract:
We present the results of an investigation of a new, large sample of brightest cluster galaxies (BCGs), their kinematic and stellar population properties and the relationships between these and the properties of the host clusters. We have obtained high signal-to-noise, long-slit spectra of 49 BCGs in the nearby Universe with the Gemini and WHT telescopes. From this, we have measured the radial velocity and velocity dispersion profiles, and used the Lick/IDS system of absorption indices to derive Single Stellar Population (SSP)-equivalent ages, metallicities and abundance ratios. These measurements were systematically compared with those of large samples of ordinary elliptical galaxies in the same mass range. In addition, the derived properties were tested for possible correlations with the internal properties of the galaxies (mass, rotation and luminosity) and the properties of the host clusters (density, mass, distance to X-ray peak and the presence of cooling flows). Here, we will highlight how the BCG kinematic and stellar population properties differ from those of ordinary giant elliptical galaxies. We will also show that there is likely to be more than one process responsible for recent star formation detected in some BCGs.