Susan Ilani Loubser
Centre for Astrophysics, University of Central Lancashire, UK.

"Stellar Populations Across cD Galaxies"

Absorption line strengths in unresolved stellar populations are becoming an increasingly popular tool by which to investigate the star formation history in early-type galaxies. We are using this technique to explore the formation and evolution of cD galaxies as a class. These are some of the most massive, brightest galaxies in the Universe and found at the centres of the gravitational potential well in clusters. We are doing long-slit spectroscopy of a statistically significant, carefully selected, sample of nearby cD galaxies. Recent observations of 25 galaxies (out of an overall target of 50) with the WHT and Gemini North and South telescopes, will enable us to measure spatially resolved line-strengths and interpret these via population modelling to derive luminosity weighted average properties. These spectra, used with our self-consistent galactic chemical evolution code, will enable us to test the predictions of the “galactic cannibalism” and “cooling flow” formation scenarios proposed for the formation of cD galaxies.

Here, I will give an overview of this project (my PhD project) and present some mid-term spectra and results.