| Description |
We propose to study the star formation history of galaxy clusters in the -yet unexplored- redshift range of0.9-2.4, at a time galaxy clusters were assembling galaxies and local massive early-type galaxies were building up,with deep PACS and SPIRE imaging on a sample of 8 high-redshift galaxy clusters and proto-clusters.We will be in a position to confirm the increase in the fraction of dusty star-forming cluster galaxiesfound by Spitzer up to z=0.8 (the mid-IR Butcher-Oemler effect) and extend it to z>1 for the first time, at wavelength close to the peak of the spectral energy distribution of star-forming galaxies. Our sample includes clusters at different mass/richnessThis will allow to understand the role and importance of environment and the physical processes by which galaxy clusters are accreting new galaxy falling from the outskirts with high star formation rates.This program promises to shed some new light too on the assembly of the oldest galaxies at z=0 by combining the clean and robust Herschel-derived SFRs (no assumptions of SEDs) and a sample of clusters that covers a broad rangein mass, age and dynamical state at previously unexplored redshifts for these wavelengths. |
