Black hole feedback – the strong interaction between the energy output of supermassive black holes and their surrounding environments – is routinely invoked to explain the absence of overly luminous galaxies , the black hole vs. bulge correlations and the similarity of black hole accretion and star formation histories .
Yet direct probes of this process in action are scarce and limited to small samples of active nuclei .
In this paper we present Gemini Integral Field Unit observations of the distribution of ionized gas around luminous , obscured , radio-quiet quasars at z \sim 0.5 .
We detect extended ionized gas nebulae via [ O iii ] \lambda 5007Å emission in every case , with a mean diameter of 28 kpc .
These nebulae are nearly perfectly round , with H \beta surface brightness declining \propto R ^ { -3.5 \pm 1.0 } .
The regular morphologies of nebulae around radio-quiet quasars are in striking contrast with lumpy or elongated [ O iii ] nebulae seen around radio galaxies at low and high redshifts .
We present the uniformly measured size-luminosity relationship of [ O iii ] nebulae around Seyfert 2 galaxies and type 2 quasars spanning six orders of magnitude in luminosity and confirm the flat slope of the correlation ( R _ { [ O~ { } { \scriptscriptstyle III } ] } \propto L _ { [ O~ { } { \scriptscriptstyle III% } ] } ^ { 0.25 \pm 0.02 } ) .
We propose a model of clumpy nebulae in which clouds that produce line emission transition from being ionization-bounded at small distances from the quasar to being matter-bounded in the outer parts of the nebula .
The model – which has a declining pressure profile – qualitatively explains line ratio profiles and surface brightness profiles seen in our sample .
It is striking that we see such smooth and round large-scale gas nebulosities in this sample , which are inconsistent with illuminated merger debris and which we suggest may be the signature of accretion energy from the nucleus reaching gas at large scales .