Measuring kinetic feedback in nearby AGN via channel maps

ABSTRACT We use velocity channel maps in the [O iii] emission line from integral-field spectroscopy obtained with the Gemini GMOS-IFU instrument to derive the ionized gas masses, mass outflow rates, and outflow powers in the central kiloparsec of 11 nearby ($z < 0.02$) active galaxies. We obtain mass-outflow rates as a function of distance from the nucleus and conclude that the highest values are observed within the inner $\approx 200~{\rm pc}$. Using these values and the whole velocity range in the channel maps, we calculate the corresponding outflow powers, that are in the range $10^{37} - 10^{42}~{\rm erg ~s^{-1}}$. We compare the results based on channel maps with those obtained using velocity-integrated measurements and find that, for all other parameter kept fixed, the use of channel maps returns higher mass-outflow rates and kinetic powers for the outflows. Our new calculations give powers that are closer to the coupling efficiencies $0.5\le \epsilon _f\le 5$ per cent which is predicted by models to have a strong effect on the host galaxy, quenching star formation, with nearly half the sources above the 0.5 per cent line.