| Description |
We propose spectroscopic observations of the primary ISM cooling lines and the high-J CO ladder in a well-defined sample of nearby elliptical and lenticular galaxies. FIR line and line/continuum ratios will be used in conjunction with PDR models to constrain the physical conditions (gas density and strength of UV radiation field) in the ISM of these early-type galaxies. Similar work has been done extensively for spiral galaxies and (U)LIRGS but has only sporadically been done for quiescent ellipticals and lenticulars. We already have a broad suite of ancillary data for our targets, including HI and CO maps, high density molecular tracers, maps of the stellar populations (ages and metallicities) and optical emission lines. Our targets make an important bridge between normal star-forming spirals and cooling flow cluster galaxies, as they have some properties in common with both other types. Thus, this project is essential for placing other Herschel approved projects into the broader context of the interactions between gas and stars across the entire Hubble sequence. |
