2012MNRAS.424L..59M

We present a detailed analysis of a highly ionized, multiphased and collimated outflowing gas detected through O V, O VI, Ne VIII and Mg X absorption associated with the QSO HE 0238–1904 (z_em ≃ 0.629). Based on the similarities in the absorption-line profiles and estimated covering fractions, we find that the O VI and Ne VIII absorption trace the same phase of the absorbing gas. Simple photoionization models can reproduce the observed N(N_eVIII), N(O VI) and N(MgX) from a single phase whereas the low-ionization species (e.g. N III, N IV and O IV) originate from a different phase. The measured N(N_e VIII)/N(O VI) ratio is found to be remarkably similar (within a factor of ∼ 2) in several individual absorption components kinematically spread over ∼ 1800 km/s. Under photoionization this requires a fine-tuning between hydrogen density (n_H) and the distance of the absorbing gas from the Quasi Stellar Object (QSO). Alternatively, this can also be explained by collisional ionization in hot gas with T ≥ 10^5.7 K. Long-term stability favours the absorbing gas being located outside the broad-line region. We speculate that the collimated flow of such a hot gas could possibly be triggered by the radio jet interaction.