Empirical Verification of the Fe II Oscillator Strengths in the FUSE Bandpass
Abstract
We report empirical determinations of atomic oscillator strengths, or f-values, for 11 ground-state transitions of Fe II in the wavelength range 1050<~λ<~1150 Å. We use ultraviolet absorption-line observations of interstellar material toward stars in the Galaxy and the Magellanic Clouds taken with Copernicus, the Goddard High Resolution Spectrograph on board the Hubble Space Telescope, and the Far-Ultraviolet Spectroscopic Explorer. We derive absolute oscillator strengths by a combination of the apparent optical depth, component-fitting, and curve-of-growth fitting techniques. Our derived oscillator strengths are generally in excellent agreement with recent theoretical calculations by Raassen & Uylings using the orthogonal operator technique. However, we identify three of the 11 transitions studied here whose f-values seem to be incompatible with these calculations by as much as a factor of 2. We suggest revisions to these f-values based on our analysis. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under the NASA contract NAS 5-26555.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2000
- DOI:
- 10.1086/317263
- arXiv:
- arXiv:astro-ph/0007236
- Bibcode:
- 2000ApJ...544..867H
- Keywords:
-
- Atomic Data;
- ISM: Abundances;
- ISM: Atoms;
- Ultraviolet: ISM;
- Astrophysics
- E-Print:
- To appear in the Astrophysical Journal. 31 pages, including 8 embedded tables and 10 embedded figures. Also available at http://fuse.pha.jhu.edu/~howk/Papers/