Wednesday, June 27, 2012
IPAC Astronomy Lunch Seminar
Measuring Gas Flows in Nearby AGN with AO Integral Field Spectroscopy
Francisco Muller-Sanchez, UCLA
I present and discuss very high angular resolution (~0.08") 2D measurements of gas flows in the nuclear environment of nearby AGN using AO-assisted integral field spectroscopy at Keck and the VLT. The spatially resolved kinematics of the ionized gas can be modeled as a combination of an outflow bicone and a rotating disk coincident with the galaxy disk. High-ionization emission is seen in both components, suggesting it is leaking out of a clumpy torus. The mass outflow rates are 23 orders of magnitude greater than the accretion rates, implying that the outflow is mass loaded by the surrounding interstellar medium (ISM). Inflows of molecular gas are found in approximately half of the sources, where they occur mostly in nuclear spiral structures or nuclear bars with mass inflow rates of ~1-10 M_sun yr-1. This is of the order of the outflow rates, suggesting that most mass which flows towards the nucleus to feed the supermassive black hole is expelled by the AGN. In half of the AGN measured so far, the kinetic energy of the outflows appears sufficient to provide the eagerly-sought ''AGN feedback'' invoked to explain fundamental galaxy properties such as the Msigma relation.