| Description |
A major cosmological event is the formation of first massive galaxies,which evolve to the luminous elliptical galaxies of today. Star formationin these galaxies was regulated and ultimately stifled by energetic AGNfeedback processes, according to simulations. However, the nature ofthese processes is open to speculation because at these enormousdistances, observations provide few constraints. Similar processes occurin some low redshift galaxy clusters where star formation and cold gas isdetected in and around the brightest cluster galaxies. These modern-dayanalogs provide us with the opportunity to understand the heating, cooling,and star formation that occur on a grand scale at high redshift. In thisHerschel Key Project, we will determine the location and mass of cooledgas, along with its temperature, ionization state, density and cooling rate.These new data, only possible with Herschel, are supplemented by radio,X-ray, and optical studies of the stars, hot gas, and AGN activity. Toaccomplish our goals, we will use PACS to measure the line strengths ofOI, OIII, NII, CII and SiI, major coolants at low temperatures thatalso reflect the ionization state of the gas. The requested PACS andSPIRE photometry will determine the distribution of dust temperaturesand masses, including the detection of the coolest gas clouds. Thesedatasets will reveal the pathway from the hot ambient medium to cool gasto star formation, a process that was widespread when the universe wasyoung. |
