Pierre Guillard - Signatures of turbulent dissipation in active galactic nuclei and galaxy interactions

In this talk I will illustrate how spectroscopic observations of key infrared cooling lines in galaxies help us to describe the physical state and the dissipation of kinetic energy in the different ISM phases, including the molecular gas. This is crucial to understand the role of turbulence in the regulation of star formation. I will focus on new follow-up observations with Palomar/TripleSpec and Herschel/PACS of galaxy interactions and radio galaxies that have powerful mid-IR H2 line emission previously detected with Spitzer. We find that in most of the sources, the kinematics of the atomic and molecular gas is dominated by turbulence. These observations are compared to new models of irradiated shocks that allow us to quantify their contribution to the near + mid-IR (H2) and far-IR (C+, OI, OIII) line emission, as well as important properties of the dissipation, like the statistical velocity distribution of these shocks.