The first 62 AGN observed with SDSS-IV MaNGA – III : stellar and gas kinematics

Abstract

We investigate the effects of active galactic nuclei (AGN) on the gas kinematics of their host galaxies, using MaNGA data for a sample of 62 AGN hosts and 109 control galaxies (inactive galaxies). We compare orientation of the line of nodes (kinematic position angle – PA) measured from the gas and stellar velocity fields for the two samples. We found that AGN hosts and control galaxies display similar kinematic PA offsets between gas and stars. However, we note that AGN have larger fractional velocity dispersion σ differences between gas and stars [σfrac = (σgas − σstars)/σstars] when compared to their controls, as obtained from the velocity dispersion values of the central (nuclear) pixel (2. 5 diameter). The AGN have a median value of σfrac of <σfrac> AGN = 0.04, while the median value for the control galaxies is <σfrac> CTR =−0.23. 75 per cent of the AGN show σfrac > −0.13, while 75 per cent of the normal galaxies show σfrac < −0.04, thus we suggest that the parameter σfrac can be used as an indicator of AGN activity. We find a correlation between the [OIII]λ5007 luminosity and σfrac for our sample. Our main conclusion is that the AGN already observed with MaNGA are not powerful enough to produce important outflows at galactic scales, but at 1–2 kpc scales, AGN feedback signatures are always present on their host galaxies.