[Normal Galaxies, Clusters of Galaxies -- Oral ]
A detailed analysis of the cores of HIFLUGCS galaxy clusters: ICM
cooling and AGN heating
Rupal Mittal, AIfA (Bonn) / RIT (Rochester)
Thomas Reiprich (AIfA), Paul Nulsen (CfA), Craig Sarazin (U. Virginia), Heinz Andernach (AIfA), Tracy Clarke (NRL), Daniel Hudson (AIfA)
The physics regulating the dense gas at the centers of galaxy
clusters is far from being fully understood. Moreover, no comprehensive
and systematic census of observed, detailed, properties of cluster cores
exists up to now. We aim to put the statistical description of clustercenters on a firm new footing in order to: (1) gain insight into the
physical processes governing cluster cores and (2) identify the best
parameter for characterizing cool-core clusters and quantify its relation
to other parameters. We summarize 16 widely used as well as new cool-core diagnostics and
apply them to the largest complete and well-controlled cluster sample
with available high quality data (HIghest X-ray FLUx Galaxy Cluster
Sample, >4.5 Ms of cleaned Chandra data). We show that the cooling flow
discrepancy is very unlikely due to the recent formation ofcooling flows, hence demonstrating the need for a heatingmechanism. Based on >140 radio flux-density measurements for the entire
HIFLUGCS sample, we provide statistical and quantitative evidence
supporting the AGN heating scenario. Lastly, we show that both ICM
cooling as well as AGN heating are likely to influence the L-T relation
but on different scales.