Large-scale outflow in quasar LBQS J1206+1052: HST/COS observations

Using two orbits of HST/COS archival observations, we measure the location and energetics of a quasar outflow from LBQS J1206+1052. From separate collisional excitation models of observed N III/N III* and S III/S III* troughs, we measure the electron number density n(e) of the outflow. Both independent determinations are in full agreement and yield n(e) = 10(3.0) cm(-3). Combining this value of n(e) with photoionization simulations, we determine that the outflow is located 840 pc from the central source. The outflow has a velocity of 1400 km s(-1), a mass flux of 9 M-circle dot yr(-1) and a kinetic luminosity of 10(42.8) erg s(-1). The distance finding is much larger than predicted from radiative acceleration models, but is consistent with recent empirical distance determinations.