We present a detailed analysis of the intrinsic UV absorption in the central HDF-S target QSO J2233-606, based on a high-resolution, high-S/N (∼25-50) spectrum obtained with VLT UVES. This spectrum samples the cluster of intrinsic absorption systems outflowing from the AGN at radial velocities v ≈-5000 to -3800 kms-1 in the key far-UV diagnostic lines: the lithium-like CNO doublets and H I Lyman series. We fit the absorption troughs using a global model of all detected lines to solve for the independent velocity-dependent covering factors of the continuum and emission-line sources and ionic column densities. This reveals increasing covering factors in components with greater outflow velocity. Narrow substructure is revealed in the optical depth profiles, suggesting that the relatively broad absorption is comprised of a series of multiple components. We perform velocity-dependent photoionization modeling, which allows a full solution to the C, N, and O abundances, as well as the velocity-resolved ionization parameter and total column density. The absorbers are found to have supersolar abundances, with [C/H] and [O/H] ≈0.5-0.9, and [N/H] ≈1.1-1.3, consistent with enhanced nitrogen production expected from secondary nucleosynthesis processes. Independent fits to each kinematic component give consistent results for the abundances. The lowest ionization material in each of the strong absorbers is modeled with similar ionization parameters. Components of higher ionization (indicated by stronger O VI relative to C IV and N V) are present at velocities just redward of each low-ionization absorber. We explore the implications of these results for the kinematic-geometric-ionization structure of the outflow.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science