Ionised Gas Kinematics in MaNGA AGN. Extents of the Narrow Line and Kinematically Disturbed regions

TL;DR

This study investigates the spatial extents of the Narrow Line Region and kinematically disturbed regions in 170 AGN host galaxies, revealing size relations, outflow properties, and their limited feedback impact on host galaxies.

Contribution

It provides the first detailed measurements of NLR and KDR extents in a large AGN sample, establishing their relation and outflow characteristics.

Findings

Most luminous AGN show higher gas-stellar velocity differences.

KDR extends about 30% of the NLR size.

Outflow rates and powers correlate with AGN luminosity, but are generally below feedback thresholds.

Abstract

We analyse the kinematics of 170 AGN host galaxies as compared to those of a matched control sample of non-active galaxies from the MaNGA survey in order to characterise and estimate the extents of the Narrow Line Region (NLR) and of the kinematically disturbed region (KDR) by the AGN. We define the observed NLR radius as the farthest distance from the nucleus within which both [Oiii]/H\beta and [Nii]/H\alpha ratios fall in the AGN region of the BPT diagram and the H\alpha equivalent width is required to be larger than 3.0\AA. The extent of the KDR is defined as the distance from the nucleus within which the AGN hosts galaxies shows a more disturbed gas kinematics than the control galaxies. The kinematics derived from the [Oiii] line profiles reveal that, on average, the most luminous AGN (L[Oiii] > 3.8 * 10^40 erg s^-1) possess higher residual difference between the gaseous and stellar velocities and velocities dispersion than their control galaxies. Spatially resolved NLR's and KDR's were found in 55 and 46 AGN host galaxies, with corrected radii 0.2 < r_KDR,c < 2.3 kpc and 0.4 < r_NLR,c < 10.1 kpc, with a relation between the two given by log r_KDR,c = (0.53\pm0.12) log r_NLR,c + (1.07\pm0.22), respectively. The extension of the KDR corresponds to about 30 per cent of that of the NLR. Assuming that the KDR is due to an AGN outflow, we have estimated ionised gas mass outflow rates that range between 10^-5 and \approx 1 Myr^-1, and kinetic powers that range from 10^34 to 10^40 erg s^-1. Comparing the power of the AGN ionised outflows with the AGN luminosities, they are always below the 0.05 L_AGN model threshold for having an important feedback effect on their respective host galaxies. The mass outflow rates (and power) of our AGN sample correlate with their luminosities, populating the lowest AGN luminosity range of the correlations previously found for more powerful sources.