Gauging the effect of supermassive black holes feedback on quasar host galaxies

In order to gauge the role that active galactic nuclei play in the evolution of galaxies via the effect of kinetic feedback in nearby QSO 2's (z ∼ 0.3), we observed eight such objects with bolometric luminosities $L_{bol} \sim 10^{46}\rm {erg\, s^{-1}}$ using Gemini Multi-Object Spectrograph-integral field units. The emission lines were fitted with at least two Gaussian curves, the broadest of which we attributed to gas kinetically disturbed by an outflow. We found that the maximum extent of the outflow ranges from ∼1 to 8 kpc, being ${\sim }\, 0.5\, {\pm }\, 0.3$ times the extent of the [ $\mathrm{O\,{\small III}}$ ] ionized gas region. Our ‘default’ assumptions for the gas density (obtained from the [ $\mathrm{S\,{\small II}}$ ] doublet) and outflow velocities resulted in peak mass outflow rates of $\dot{M}_{\mathrm{ out}}^{{\tt def}}\sim$  3–30  $\rm {M_{\odot }}\, yr^{-1}$ and outflow power of $\dot{E}_{\mathrm{ out}}^{{\tt \mathrm{ def}}}\sim \, 10^{41}$ – $10^{43}\, \mathrm{erg\, s^{-1}}$ . The corresponding kinetic coupling efficiencies are $\varepsilon _f^{{\tt def}}=\dot{E}_{\mathrm{ out}}^{{\tt def}}/L_{\mathrm{ bol}}\, \sim 7\times 10^{-4}$ –0.5 per cent, with the average efficiency being only 0.06 per cent (0.01 per cent median), implying little feedback powers from ionized gas outflows in the host galaxies. We investigated the effects of varying assumptions and calculations on $\dot{M}_{\mathrm{ out}}$ and $\dot{E}_{\mathrm{ out}}$ regarding the ionized gas densities, velocities, masses, and inclinations of the outflow relative to the plane of the sky, resulting in average uncertainties of 1 dex. In particular, we found that better indicators of the [ $\mathrm{O\,{\small III}}$ ] emitting gas density than the default [ $\mathrm{S\,{\small II}}$ ] line ratio, such as the [ $\mathrm{Ar\,{\small IV}}$ ] λλ4711,40 line ratio, result in almost an order of magnitude decrease in the ε f .