| Description |
We propose a definitive census of obscured star formation in intermediate redshift clusters and its relationship with the recent mass assembly and thermodynamic histories of the clusters. Specifically, we propose to use Herschel/PACS observations at 100 and 160um in conjunction with our Spitzer 24um data to characterize the dust-obscured galaxy populations (star formation rate, AGN contamination, bolometric IR luminosity, dust temperature) in a large unbiased sample of galaxy clusters at 0.15<z<0.3. The sample of 32 clusters is drawn from the Local Cluster Substructure Survey (LoCuSS) for which outstanding supporting data are available, including gravitational lensing, X-ray spectro-imaging, and Spitzer 24um maps. This unprecedented dataset on a large and unbiased cluster sample will enable us to answer definitively the question: what physical process(es) are responsible for triggering obscured star-formation in cluster galaxies?. The enduring legacy will be a baseline study of the demographics of low-intermediate redshift clusters against which to compare and thus interpret the rapidly growing menagerie of high redshift cluster observations. This will be achieved through a series of public data releases, that will include quantities derived from the Herschel data (e.g. L_IR, T_dust) and from our huge investment in supporting data (e.g. dark matter density, galaxy redshifts, galaxy morphologies). All of this can be achieved with a modest Key Programme of 145 hours duration. |
