| Description |
A major cosmological event is the formation of first massive galaxies,
which evolve to the luminous elliptical galaxies of today. Star formation
in these galaxies was regulated and ultimately stifled by energetic AGN
feedback processes, according to simulations. However, the nature of these
processes is open to speculation because at these enormous distances,
observations provide few constraints. Similar processes occur in some low
redshift galaxy clusters where star formation and cold gas is detected in
and around the brightest cluster galaxies. These modern-day analogs provide
us with the opportunity to understand the heating, cooling, and star
formation that occur on a grand scale at high redshift. In this Herschel
Key Project, we will determine the location and mass of cooled gas, 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. To accomplish our
goals, we will use PACS to measure the line strengths of [OI], [OIII], [NII],
[CII] and [SiI], major coolants at low temperatures that also reflect the
ionization state of the gas. The requested PACS and SPIRE photometry will
determine the distribution of dust temperatures and masses, including the
detection of the coolest gas clouds. These datasets will reveal the pathway
from the hot ambient medium to cool gas to star formation, a process that
was widespread when the universe was young. |
