Contact Name: Cristian Vignali
Abstract:
Evidence is now mounting that most of the activity in luminous infrared galaxies takes place in their compact obscured nuclei (CONs), regions of less than 100 pc in diameter, which harbor large amounts of warm (T>100K) molecular material (NH>10^{24}cm-2). The extreme obscuration makes it impossible to study the central regions of such objects with conventional Optical/IR diagnostics and the nature of the activity (Starburt or AGN) is often unknown. However, the combined effect of warm, shielded gas and intense infrared radiation produce rich molecular mm-wavelength spectra, which can be used as probes of the physical properties of the compact nuclear regions. Also, mm observations provide important information on the energetics and Star-formation/AGN feedback via the detection of molecular out- and in- flows. In my talk I will report some results from early science ALMA observations, showing how the unprecedented sensitivity of the ALMA observatory has revolutionized the study of obscured LIRGs in the near and far Universe.