In massive galaxies the AGN at the core can have a profound effect on its host galaxy from their formation to the present day. This effect is particularly important in the cores of clusters of galaxies where the AGN is believed to be strongly suppressing the cooling of the hot intracluster gas that surrounds the brightest cluster galaxy (BCG). We propose to obtain PACS photometry and spectroscopy of four BCGs that have strong AGN characteristics ([OIII] line, MIR continuum and-or flat spectrum radio continuum). These four systems are the most extreme BCGs selected from a sample of over one thousand X-ray selected clusters and hence can be used to constrain the energetics and duty cycle of AGN in a statistically meaningful sample of clusters. The Herschel data will reveal important diagnostics of the individual AGN that can be applied to weak AGN in the larger sample.
Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.