Distance, Energy, and Variability of Quasar Outflows: Two HST/COS Epochs of LBQS 1206+1052

Abstract

We analyze new HST/COS spectra for two quasar absorption outflows seen in the quasi-stellar object LBQS 1206+1052. These data cover, for the first time, absorption troughs from S IV, Si II, and P V. From the ratio of the S IV* to S IV column densities, we measure the electron number density of the higher-velocity (-1400 km s^-1, v1400) outflow to be {log}({n}_e)={4.23}_-0.09^+0.09 cm^-3 and constrain the lower-velocity (-730 km s^-1, v700) outflow to log(n _e ) > 5.3 cm^-3. The n _e associated with the higher-velocity outflow is an order of magnitude larger than reported in prior work. We find that the previous measurement was unreliable since it was based on density-sensitive absorption troughs that were likely saturated. Using photoionization models, we determine the best χ ²-minimization fit for the ionization parameter and hydrogen column density of the higher-velocity outflow: log({U}_{{H}})=-{1.73}_-0.12^+0.21 and log({N}_{{H}})={21.03}_-0.15^+0.25 cm^-2, respectively. We calculate from U _H and n _e a distance of {500}_-110⁺¹⁰⁰ pc from the central source to the outflow. Using an SED attenuated by the v700 outflow yields a two-phase photoionization solution for the v1400 outflow, separated by a {{Δ }}U≈eq 0.7. Otherwise, the resultant distance, mass flux, and kinetic luminosity are similar to the unattenuated case. However, the attenuated analysis has significant uncertainties due to a lack of constraints on the v700 outflow in 2017.

Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555.