Fueling AGN II: Spatially Resolved Molecular Inflows and Outflows

TL;DR

This study investigates the spatial distribution and movement of stars and molecular gas in the central regions of active and inactive galaxies, revealing inflows and outflows that influence galaxy evolution.

Contribution

It provides detailed kinematic analysis of molecular inflows and outflows in AGN, demonstrating their connection to large-scale structures and galaxy environment.

Findings

Steady-state inflows observed in three AGN, driven by large-scale bars.

Molecular outflows spatially resolved in three AGN, with low speeds leading to fallback.

Inactive galaxies show chaotic dust and counter-rotating molecular structures.

Abstract

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