2007ApJ...666..794F

We present Gemini integral field spectroscopy and Keck II long-slit spectroscopy of the extended emission-line region (EELR) around the quasar 4C 37.43. The velocity structure of the ionized gas is complex and cannot be explained globally by a simple dynamical model. The spectra from the clouds are inconsistent with shock or ``shock + precursor'' ionization models, but they are consistent with photoionization by the quasar nucleus. The best-fit photoionization model requires a low-metallicity [12+log(O/H)≲8.7] two-phase medium, consisting of a matter-bounded diffuse component with a unity filling factor (N∼1/cm3, T∼15,000 K), in which are embedded small, dense clouds (N∼400/cm3, T∼10<sup>4</sup> K). The high-density clouds are transient and can be regenerated through compressing the diffuse medium by low-speed shocks (V<sub>S</sub>≲100 km/s). Our photoionization model gives a total mass for the ionized gas of about 3x10<sup>10</sup> M<sub>☉</sub>, and the total kinetic energy implied by this mass and the observed velocity field is ∼2x10<sup>58</sup> erg. The fact that luminous EELRs are confined to steep-spectrum radio-loud QSOs, yet show no morphological correspondence to the radio jets, suggests that the driving force producing the 4C 37.43 EELR was a roughly spherical blast wave initiated by the production of the jet. That such a mechanism seems capable of ejecting a mass comparable to that of the total interstellar medium of the Milky Way suggests that ``quasar-mode'' feedback may indeed be an efficient means of regulating star formation in the early universe.