Photoionized O VI absorbers toward the bright QSO HE 0515-4414 ?

We report on detailed Monte Carlo inversion analysis of five $\ion{O}{vi}$ systems from the spectrum of the bright quasar HE 0515–4414 ($z_{\rm em}\,$= 1.71). The associated system at $z_{\rm abs}\,$= 1.697 with the neutral hydrogen column density N ($\ion{H}{i}$) $= 4.4\times10^{13}$ cm -2 shows pronounced absorption from highly ionized transitions of $\ion{C}{iii}$, $\ion{C}{iv}$, $\ion{N}{v}$, $\ion{O}{vi}$, $\ion{Si}{iv}$, and probably $\ion{S}{vi}$. We found that only a power law type ionizing spectrum ($J_\nu \propto \nu^{-1.5}$) is consistent with the observed sample of the line profiles, i.e. the system is definitely intrinsic. The relative metal abundances give almost the solar pattern and the metallicity of ~5 times solar. The system originates in a thin shell of the line-of-sight thickness $L \la 16$ pc. Two $\ion{O}{vi}$ systems at $z_{\rm abs}\,$= 1.674 ([C/H] $\simeq -1.6$) and 1.602 ([O/H] $\simeq -1.1$), arising in intervening halos, have linear sizes of $L \simeq$ 3–14 kpc and $\simeq$17 kpc, respectively. Absorption systems at $z_{\rm abs}\,$= 1.385 ([C/H] $\simeq -0.3$, $L \simeq$ 1.7–2.5 kpc) and $z_{\rm abs}\,$= 1.667 ([C/H] $ \simeq -0.5$, $L \simeq 1$ kpc) exhibit characteristics very similar to that observed in metal-enriched high velocity clouds in the Milky Way. These systems are probably embedded in extremely metal-poor halos with [C/H] $ α systems at $z_{\rm abs}\,$= 1.500 and 1.681 with, respectively, N ($\ion{H}{i}$) $\simeq 1.7\times10^{15}$ and $1.8\times10^{15}$ cm -2 and [C/H] $ 10^5$ K is negligible in these systems.