Quasar outflows and AGN feedback in the extreme UV: HST/COS observations of HE 0238−1904

• Published in: Monthly notices of the Royal Astronomical Society 2013-12, Vol.436 (4), p.3286-3305
• Main Authors: Arav, Nahum, Borguet, Benoit, Chamberlain, Carter, Edmonds, Doug, Danforth, Charles
• Format: Article
• Language: English
• Subjects: Ions; Quasars; Spectrum analysis; Stars & galaxies
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stt1812

Spectroscopic observations of quasar outflows at rest-frame 500-1000 A have immense diagnostic power. We present analyses of such data, where absorption troughs from OIV and OIV* allow us to obtain the distance of the outflows from the AGN and troughs from Ne VIII and Mg X reveal the warm absorber phase of the outflow. Their inferred column densities, combined with those of O VI, N IV and ..., yield two important results. (1) The outflow shows two ionization phases, where the high-ionization phase carries the bulk of the material. This is similar to the situation seen in X-ray warm absorber studies. Furthermore, the low-ionization phase is inferred to have a volume filling factor of ... (2) We determine a distance of 3000 pc from the outflow to the central source using the O IV*/O IV column density ratio and the knowledge of the ionization parameter. Since this is a typical high-ionization outflow, we can determine robust values for the outflow's mass flux and kinetic luminosity of 40 M... yr... and ..., respectively, where the latter is roughly equal to 1 per cent of the bolometric luminosity. Such a large kinetic luminosity and mass flow rate measured in a typical high-ionization wind suggest that quasar outflows are a major contributor to AGN feedback mechanisms. (ProQuest: ... denotes formulae/symbols omitted.)