FUELING ACTIVE GALACTIC NUCLEI. II. SPATIALLY RESOLVED MOLECULAR INFLOWS AND OUTFLOWS

Abstract

We analyse the 2-dimensional distribution and kinematics of the stars as well\nas molecular and ionised gas in the central few hundred parsecs of 5 active and\n5 matched inactive galaxies. The equivalent widths of the Br-gamma line\nindicate there is no on-going star formation in their nuclei, although recent\n(terminated) starbursts are possible in the active galaxies. The stellar\nvelocity fields show no signs of non-circular motions, while the 1-0S(1) H_2\nkinematics exhibit significant deviations from simple circular rotation. In the\nactive galaxies the H_2 kinematics reveal inflow and outflow superimposed on\ndisk rotation. Steady-state circumnuclear inflow is seen in three AGN, and\nhydrodynamical models indicate it can be driven by a large scale bar. In three\nof the five AGN, molecular outflows are spatially resolved. The outflows are\noriented such that they intersect, or have an edge close to, the disk - which\nmay be the source of molecular gas in the outflow. The relatively low speeds\nimply the gas will fall back onto the disk; and with moderate outflow rates,\nthey will have only a local impact on the host galaxy. H_2 was detected in two\ninactive galaxies. These exhibit chaotic circumnuclear dust morphologies and\nhave molecular structures that are counter-rotating with respect to the main\ngas component, which could lead to gas inflow in the near future. In our\nsample, all four galaxies with chaotic dust morphology in the circumnuclear\nregion exist in moderately dense groups with 10-15 members where accretion of\nstripped gas can easily occur.