Supermassive black hole feeding and feedback observed on sub-parsec scales

Abstract

Active galaxies contain a supermassive black hole at their center, which grows by accreting matter from the surrounding galaxy. The accretion process in the central ~10 parsecs has not been directly resolved in previous observations, due to the small apparent angular sizes involved. We observed the active nucleus of the Circinus Galaxy using sub-millimeter interferometry. A dense inflow of molecular gas is evident on sub-parsec scales. We calculate that less than 3% of this inflow is accreted by the black hole, with the rest being ejected by multiphase outflows, providing feedback to the host galaxy. The observations also reveal a dense gas disk surrounding the inflow; the disk is gravitationally unstable which drives the accretion into the central ~1 parsec.