We present HST /COS observations of highly ionized absorption lines associated with a radio-loud QSO at z = 1.1319 .
The absorption system has multiple velocity components , with an overall width of \approx 600 km s ^ { -1 } , tracing gas that is largely outflowing from the QSO at velocities of a few 100 km s ^ { -1 } .
There is an unprecedented range in ionization , with detections of H I , N III , N IV , N V , O IV , O IV * , O V , O VI , Ne VIII , Mg X , S V and Ar VIII .
We estimate the total hydrogen number density from the column density ratio N ( \textrm { O } \textsc { iv* } ) / N ( \textrm { O } \textsc { iv } ) to be \log ( n _ { \textrm { H } } / \textrm { cm } ^ { -3 } ) \sim 3 .
Combined with constraints on the ionization parameter in the O IV bearing gas from photoionization equilibrium models , we derive a distance to the absorbing complex of 2.3 \mathrel { \hbox { \hbox to 0.0 pt { \hbox { \lower 4.0 pt \hbox { $ \sim$ } } } \hbox { $ < $ } } } % R \mathrel { \hbox { \hbox to 0.0 pt { \hbox { \lower 4.0 pt \hbox { $ \sim$ } } } \hbox { $ < $ } } } 6. % 0 ~ { } \textrm { kpc } from the centre of the QSO .
A range in ionization parameter , covering \sim 2 orders of magnitude , suggest absorption path lengths in the range 10 ^ { -4.5 } \mathrel { \hbox { \hbox to 0.0 pt { \hbox { \lower 4.0 pt \hbox { $ \sim$ } } } \hbox { % $ < $ } } } l _ { \textrm { abs } } \mathrel { \hbox { \hbox to 0.0 pt { \hbox { \lower 4.0 pt \hbox { $% \sim$ } } } \hbox { $ < $ } } } 1 ~ { } \textrm { pc } .
In addition , the absorbing gas only partially covers the background emission from the QSO continuum , which suggests clouds with transverse sizes l _ { \textrm { trans } } \mathrel { \hbox { \hbox to 0.0 pt { \hbox { \lower 4.0 pt \hbox { $ \sim$% } } } \hbox { $ < $ } } } 10 ^ { -2.5 } ~ { } \textrm { pc } .
Widely differing absorption path lengths , combined with covering fractions less than unity across all ions pose a challenge to models involving simple cloud geometries in associated absorption systems .
These issues may be mitigated by the presence of non-equilibrium effects , which can be important in small , dynamically unstable clouds , together with the possibility of multiple gas temperatures .
The dynamics and expected lifetimes of the gas clouds suggest that they do not originate from close to the AGN , but are instead formed close to their observed location .
Their inferred distance , outflow velocities and gas densities are broadly consistent with scenarios involving gas entrainment or condensations in winds driven by either supernovae , or the supermassive black hole accretion disc .
In the case of the latter , the present data most likely does not trace the bulk of the outflow by mass , which could instead manifest itself as an accompanying warm absorber , detectable in X-rays .