[CII] absorption and emission in the diffuse interstellar medium across the Galactic Plane

Séminaire IPAG de Maryvonne Gerin (LERMA), jeudi 6 novembre 2014 à 11h00, IPAG seminar room

C+ is the main reservoir of carbon in the diffuse interstellar medium. The Herschel satellite has enabled high spectral resolution observations of the fine structure line [CII] at 1.9 THz in a wide variety of sources. In this talk, I will present absorption measurements of the [CII] fine structure line soundinfg the diffuse interstellar medium long sight-lines towards massive star forming regions. These data are combined with Herschel data of the fine structure lines of atomic oxygen and carbon and ground based observations. From this data set, we have determined the gas densities and pressure along the probed sight-lines, as well as the gas phase carbon abundance. I will also discuss the gas cooling rate and the filling factor of the diffuse gas.