1998/06/06 by F. Hamann, Hamann, F.
Engineering · Materials Science · Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #Gas Sensing Nanomaterials and Sensors #Nuclear Physics and Applications #Solid-state spectroscopy and crystallography #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9806101
7 pages LaTeX with 2 figs. embedded
arxiv created 1998/06/06 · openalex publication_date 1998/06/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Several studies have shown that the column densities inferred from broad absorption lines (BALs) require extremely high metallicities and phosphorus overabundances -- apparently in conflict with other abundance diagnostics. Here I use HST spectroscopy of the BALQSO PG 1254+047 to argue that the BALs abundance estimates are incorrect, because partial line-of-sight coverage of the continuum source(s) has led to gross underestimates of the line optical depths and column densities. I claim that the significant presence of PV 1118,1128 absorption in this and other BALQSOs identifies the saturated absorption-line spectrum. This interpretation implies that the total column densities are at least ten times larger than previous estimates, namely log NH(cm-2) > 22. The outflowing BAL gas, at velocities from -15,000 to -27,000 km/s in PG 1254+047, is therefore a strong candidate for the X-ray absorber in BALQSOs. If this high-column density outflow is radiately accelerated, it must originate <0.1 pc from the QSO.