Understanding the physics of cold gas in the nearby proxies of distant cooling cores

We propose to observe nine nearby Halpha and Xray bright giant elliptical galaxies to study the physical properties of their coldest gas phases. Recent CO and IR observationsreveal that giant elliptical galaxies contain large amounts of cold dust and gas. These systems also often exhibit powerful Halpha emission, but relatively little star formation. These nearby massive galaxies arethe lowest redshift proxies of the more distant cluster cooling cores.The first goal of the proposed observations is to understand the physical properties of the coldest gas phases in the nearest, most massive giant elliptical galaxies and to correlate them with the Xray properties of these systems to understand why this cold gas does not proceed to starformation. Furthermore, in these galaxies a tight correlation has been found between the their Bondi accretion rate ofhot gas and the jet power. An important question, that we seek to answer is: is this correlation so tight because of a steady accretion of hot gas only, or is there another tight correlation between the hot and cold gas phases, leading to an apparent correlation between the Bondi accretion and the jet power?In order to address these question, we will use Herschel to target the atomic cooling lines of CII and OI. The proposed Herschel PACS observation in combination with existing and upcoming CO, NIR,optical, UV, Xray, and radio data, will allow us to test our ideas about the mixing of the cold and hot gas phases in the nearest, brightest giant elliptical galaxies and to discriminate betweenmodels of heat input into the cold gas by mixing layers and alternative models, such as heating by conduction or shock heating from colliding clouds. In combination with existing and upcoming CO observations, we will be able to determine the mass of the cold gas in the cores of these giant elliptical galaxies. This will enable us to look for a possible relation between the hot and col tru [truncated!, Please see actual data for full text]