2005/12/15 by M. F. Gu, Ming F. Gu, Tomer Holczer +3 · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Atmospheric Ozone and Climate #Atomic and Molecular Physics #Solar and Space Plasma Dynamics #astro-ph
paper · pdf · doi:10.1086/500640
published as Astrophys.J.641:1227-1232,2006 · Accepted for publication in ApJ
arxiv created 2005/12/15 · openalex publication_date 2006/04/14 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We provide improved atomic calculation of wavelengths, oscillator strengths, and autoionization rates relevant to the 2 → 3 inner-shell transitions of Fe VI-XVI, the so-called Fe M-shell unresolved transition array (UTA). A second-order many-body perturbation theory is employed to obtain accurate transition wavelengths, which are systematically larger than previous theoretical results by 15-45 mÅ. For a few transitions of Fe XVI and Fe XV for which laboratory measurements exist, our new wavelengths are accurate to within a few mÅ. Using these new calculations, the apparent discrepancy in the velocities between the Fe M-shell UTA and other highly ionized absorption lines in the outflow of NGC 3783 disappears. The oscillator strengths in our new calculation agree well with the previous theoretical data, while the new autoionization rates are significantly larger, especially for lower charge states. We attribute this discrepancy to the missing autoionization channels in the previous calculation. The increased autoionization rates may slightly affect the column density analysis of the Fe M-shell UTA for sources with high column density and very low turbulent broadening. The complete set of atomic data is provided as an electronic table.