Ionised gas outflow signatures in SDSS-IV MaNGA active galactic nuclei

TL;DR

This study analyzes ionised gas kinematics in 2778 galaxies from SDSS-IV MaNGA, revealing that AGN exhibit more prevalent high-velocity outflows than non-AGN, though their impact on galaxy evolution appears limited.

Contribution

It provides a detailed kinematic analysis of ionised gas in a large galaxy sample, highlighting the prevalence of outflows in low-luminosity AGN and their potential long-lived feedback signatures.

Findings

High-velocity gas is more common in AGN than non-AGN.

Higher luminosity AGN drive larger scale outflows.

Feedback efficiencies are estimated to be less than 1%.

Abstract

The prevalence of outflow and feedback signatures in active galactic nuclei (AGN) is a major unresolved question which large integral field unit (IFU) surveys now allow to address. In this paper, we present a kinematic analysis of the ionised gas in 2778 galaxies at z $\sim$ 0.05 observed by SDSS-IV MaNGA. Specifically, we measure the kinematics of the [OIII] {\lambda}5007{\AA} emission line in each spatial element and fit multiple Gaussian components to account for possible non-gravitational motions of gas. Comparing the kinematics of the ionised gas between 308 MaNGA-selected AGN that have been previously identified through emission line diagnostics and sources not classified as AGN, we find that while 25% of MaNGA-selected AGN show [OIII] components with emission line widths of $>$ 500 km/s in more than 10% of their spaxels, only 7% of MaNGA non-AGN show a similar signature. Even the AGN that do not show nuclear AGN photoionisation signatures and that were only identified as AGN based on their larger scale photoionisation signatures show similar kinematic characteristics. In addition to obscuration, another possibility is that outflow and mechanical feedback signatures are longer lived than the AGN itself. Our measurements demonstrate that high velocity gas is more prevalent in AGN compared to non-AGN and that outflow and feedback signatures in low-luminosity, low-redshift AGN may so far have been underestimated. We show that higher luminosity MaNGA-selected AGN are able to drive larger scale outflows than lower luminosity AGN. But estimates of the kinetic coupling efficiencies are $<$ 1% and suggest that the feedback signatures probed in this paper are unlikely to have a significant impact on the AGN host galaxies. However, continuous energy injection may still heat a fraction of the cool gas and delay or suppress star formation in individual galaxies even when the AGN is weak.