2003/04/30 by F. Hamann, B. Sabra, Hamann, F. +10
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #Geophysics and Gravity Measurements #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0304564
4-page proceedings for the workshop, "X-Ray Spectroscopy of AGN with Chandra and XMM," Garching, Germany, December 2001
arxiv created 2003/04/30 · openalex publication_date 2003/04/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We are involved in a program to derive properties of broad absorption line (BAL) winds in quasars using combined UV and X-ray observations. A major obstacle is large uncertainties in the derived BAL column densities because of partial coverage of the background light source. In this preliminary report, we circumnavigate those uncertainties by making a simple assumption -- that the relative metal abundances are roughly solar. In this case, the PV 1118,1128 multiplet should have at least 500 times lower optical depth than CIV 1549,1551. Nonetheless, a PV BAL is present in at least half of the well-measured BALQSOs we studied. We conclude that the strong lines of abundant species like CIV are typically very optically thick. The total BAL column densities are NH > 1022 cm-2 (for solar overall metallicity), and they might be comparable to the X-ray absorbers, of order 1023 cm-2, if the BAL gas is sufficiently ionized. If the column densities in outflowing BAL gas are, in fact, as large as the X-ray absorbers, it would present a serious challenge to models of radiatively-driven BAL winds.