Molecular Gas and Nuclear Activity in Galaxies with ALMA

In pre ALMA epoch, studies of molecular gas in Active Galactic Nucleus (AGN) circumnuclear regions were hampered by insufficient spatial resolution and sensitivity to trace the gas inside a 100 pc radius. The first cycles of ALMA have already offered the opportunity, for the first time, to examine the ultimate contenders of nuclear gas fueling, (nuclear bars, dynamical friction, and/or turbulent viscosity) improving spatial resolution and sensitivity. I will present ALMA molecular gas maps in nearby active galaxies at the unprecedented spatial resolution of ~5-20 pc. These data are fundamental to test and refine the scenario of feeding and feedback of AGN, and constrain black hole models. ALMA is also allowing us to tackle and resolve the molecular torus below 10 pc