Back to Volume
Paper: Active Galactic Nuclei at the Smallest Scales: Infall and Obscuration
Volume: 487, Resolving The Future Of Astronomy With Long-Baseline Interferometry
Page: 199
Authors: Storchi-Bergmann, T.
Abstract: Active Galactic Nuclei (AGN) probe crucial phases in the evolution of galaxies, which seem to regulate both the growth of the Supermassive Black Hole (SMBH) via mass accretion and of the galaxy via AGN feedback. The relevant physical processes occur at scales ranging from 10–6 parsecs (pc) (Event Horizon) through 10–3 pc (Accretion Disk), 10–2 pc (Broad Line Region—BLR), and 10–1–100 pc (Dusty Torus) to 101–103 pc ( Narrow-Line Region—NLR). Studies using the technique of near-IR interferometry are already probing the dusty torus in the closest AGN. On larger scales (10–100 pc), observations with Integral Field Units (IFUs) at large (8m) telescopes are being used not only to map the usual outflows (feedback) observed in the NLR but also to look for inflows that feed the AGN. In the near-IR, observations with the Gemini instrument NIFS and Very Large Telescope instrument SINFONI reveal structures in hot (2000K) molecular hydrogen whose kinematics are dominated by rotation or inflow, suggesting that they are fueling the AGN. In the optical, Hubble Space Telescope imaging shows dusty spirals and filaments, interpreted as being tracers of fueling flows to the AGN, what has been confirmed in a few cases via optical IFU spectroscopy using ionized gas emission lines. These IFU observations are providing the first estimates of mass inflow rates to the AGN as well as the mapping of the inflow processes. These studies will be complemented in the near future with observations of the cold molecular gas with the Atacama Large Millimeter Array—ALMA. But further progress—to scales smaller than those of the torus, such as that of the BLR (0.01 pc), will only be possible using the technique of optical and near-infrared interferometry.
Back to Volume