VUV oscillator strengths for iron lines of astrophysical importance

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningfagfællebedømt

FeII lines are of great importance in analyses of stars and nebulae, not only for abundance studies, but also for diagnostics of the plasma conditions and derivation of physical properties such as temperature, electron density and radiation field. We present a project where the ultimate goal is to derive transition rates for specific Fe II 4s - 5p transitions at VUV wavelengths. These are important for many astrophysical applications, e.g. in objects where line fluorescence is prominent as well as stars observed in the ultraviolet FUSE and HST/STIS region. In this wavelength region many other iron-group element ions have important transitions, which also will be measured. This work is performed as absorption measurements using a FeII hollow-cathode discharge, illuminated by synchrotron radiation at the MAX-lab facility (Lund, Sweden). The intensity ratio between absorption lines from a specific lower level can be determined, and transformed to an absolute scale using previously known f-values for a few lines. We present results from low spectral resolution test runs on MAX-I, and outline the next step with its requirements for a high-resolution setup at MAX-III.

OriginalsprogEngelsk
Artikelnummer012010
BogserieJournal of Physics: Conference Series
Vol/bind130
ISSN1742-6588
DOI
StatusUdgivet - 2008

ID: 236121939