Gauging the effect of Supermassive Black Holes feedback on Quasar host galaxies

Abstract

In order to gauge the role that active galactic nuclei (AGN) play in the evolution of galaxies via the effect of kinetic feedback in nearby QSO$\,$2's ($z\sim0.3$), we observed eight such objects with bolometric luminosities $L_{bol} \sim 10^{46}\rm{erg\,s^{-1}}$ using Gemini GMOS-IFU's. 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 $\sim$1 to 8 kpc, being ${\sim}\,0.5\,{\pm}\,0.3$ times the extent of the [O$\,$III] ionized gas region. Our `${\tt default}$' assumptions for the gas density (obtained from the {[S$\,$II] doublet) and outflow velocities resulted in peak mass outflow rates of $\dot{M}_{out}^{\tt defa}{\sim}\,3\,{-}\,30\,\rm{M_{\odot}}\,yr^{-1}$ and outflow power of $\dot{E}_{out}^{\tt defa}\sim\,10^{41}\,{-}\,10^{43}\,\mathrm{erg\,s^{-1}}$. The corresponding kinetic coupling efficiencies are $\varepsilon_f^{\tt defa}=\dot{E}_{out}^{\tt defa}/L_{bol}\,\sim7\times10^{-4}\,{-}\,0.5\,\%$, with the average efficiency being only $0.06\,\%$ ($0.01\,\%$ median), implying little feedback powers from ionized gas outflows in the host galaxies. We investigated the effects of varying assumptions and calculations on $\dot{M}_{out}$ and $\dot{E}_{out}$ regarding the ionized gas densities, velocities, masses and inclinations of the outflow relative to the plane of the sky, resulting in average uncertainties of one dex. In particular, we found that better indicators of the [O$\,$III] emitting gas density than the default [S$\,$II] line ratio, such as the [Ar$\,$IV]$λλ$4711,40 line ratio, result in almost an order of magnitude decrease in the $\varepsilon_f$.