Gemini NIFS survey of feeding and feedback in nearby Active Galaxies -- V. Molecular and Ionised Gas Kinematics

TL;DR

This study investigates the gas distribution and kinematics in the inner regions of six nearby Seyfert galaxies, revealing rotation, outflows, and inflows of ionised and molecular gas, with implications for AGN feeding and feedback processes.

Contribution

The paper provides detailed kinematic analysis of ionised and molecular gas in Seyfert galaxies using NIFS data, highlighting the coexistence of inflows and outflows and their impact on AGN activity.

Findings

Ionised gas outflows are present in four galaxies with velocities of a few hundred km/s.

H2 outflows are detected in three galaxies, indicating molecular gas feedback.

Inflow velocities of 50-80 km/s suggest ongoing gas accretion, but at rates lower than AGN accretion needs.

Abstract

We study the gas distribution and kinematics of the inner kpc of six moderately luminous (43.43$\leq$log$L_{\rm bol}\leq$44.83) nearby ($0.004 \leq z \leq 0.014$) Seyfert galaxies observed with the Near-infrared Integral Field Spectrograph (NIFS) in the J(1.25$\mu$m) and K(2.2$\mu$m) bands. We analyse the most intense emission lines detected on these spectral wavebands: [Fe II] 1.2570 $\mu$m and Pa$\beta$, which trace the ionised gas in the partially and fully ionised regions, and H$_2$2.1218$\mu$m, that traces the hot ($\sim 2000$ K) molecular gas. The dominant kinematic component is rotation in the disc of the galaxies, except for the ionised gas in NGC 5899 which shows only weak signatures of a disc component. We find ionised gas outflow in four galaxies, while signatures of H$_2$ outflows are seen in three galaxies. The ionised gas outflows display velocities of a few hundred km\,s$^{-1}$, and their mass-outflow rates are in the range $0.005 - 12.49$M$_{\odot}$yr$^{-1}$ . Their kinetic powers correspond to $0.005-0.7$ per cent of the AGN bolometric luminosities. Besides rotation and outflows signatures in some cases, the H 2 kinematics reveals also inflows in three galaxies. The inflow velocities are $50-80$km\,s$^{-1}$ and the mass inflow rates are in the range $1 - 9 \times 10^{-4}$M$_{\odot}$yr$^{-1}$ for hot molecular gas. These inflows might be only the hot skin of the total inflowing gas, which is expected to be dominated by colder gas. The mass inflow rates are lower than the current accretion rates to the AGN, and the ionised outflows are apparently disturbing the gas in the inner kpc.