Colloquium on 3 April 2014
Assembly of stellar mass in cluster cores since z=1


Title: Assembly of stellar mass in cluster cores since z=1
Speaker: Claire Burke
Date: Thursday, 3 April 2014
Time: 11:00 - 12:00
Venue: SAAO Auditorium


The formation and evolution of brightest cluster galaxies (BCGs) is a topic of much recent debate in both observational and theoretical studies, with  a range of evolutionary scenarios being reported by observes and striking disagreements being found between simulated and observed BCG properties. For example, some observational studies report no growth in mass for BCGs since z=1 whilst others find a doubling in mass over this time, for the same timescale simulations predict up to a quadrupling in mass of these galaxies. Complementary to these results, it has recently become clear that the stars found in the diffuse intracluster light (ICL) form a major component of cluster stellar mass and its evolution is linked very closely with that of BCGs. Currently the general consensus is that the ICL has grown and evolved significantly, increasing in terms of its contribution to the total cluster light by more than a factor of 4 since z=1, however the mechanisms responsible for this remain unclear. I will present the results of our recent study of mergers in BCGs and the buildup of the ICL since z=1 using deep multi-wavelength data from the CLASH survey. We find surprising new evidence for very little growth of the ICL and BCG, with very few mergers taking place in cluster cores.

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