Title: The OIV and SIV intercombination lines in the ultraviolet spectra of astrophysical sources
Authors: Keenan, FP ×
Ahmed, S
Brage, T
Doyle, JG
Espey, BR
Exter, Katrina
Hibbert, A
Keenan, MTC
Madjarska, MS
Mathioudakis, M
Pollacco, DL #
Issue Date: Dec-2002
Publisher: Blackwell publishing ltd
Series Title: Monthly notices of the royal astronomical society vol:337 issue:3 pages:901-909
Abstract: New electron density diagnostic line ratios are presented for the O IV 2s(2)2p P-2-2s2p(24)P and S IV 3s(2)3p P-2-3s3p(24)P intercombination lines around 1400 Angstrom comparison of these with observational data for the symbiotic star RR Telescopii (RR Tel), obtained with the Space Telescope Imaging Spectrograph (STIS), reveals generally very good agreement between theory and observation. However the S IV P-2(3/2)-P-4(1/2) transition at 1423.824 Angstrom is found to be blended with an unknown feature at 1423.774 Angstrom. The linewidth for the latter indicates that the feature arises from a species with a large ionization potential. In addition, the S IV P-2(1/2)-P-4(3/2) transition at 1398.044 Angstrom is identified for the first time (to our knowledge) in an astrophysical source other than the Sun, and an improved wavelength of 1397.166 Angstrom is measured for the O IV P-2(1/2)-P-4(3/2) line. The O IV and S IV line ratios in a sunspot plume spectrum, obtained with the Solar Ultraviolet Measurements of the Emitted Radiation (SUMER) instrument on the Solar and Heliospheric Observatory, are found to be consistent, and remove discrepancies noted in previous comparisons of these two ions.
ISSN: 0035-8711
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Non-KU Leuven Association publications
× corresponding author
# (joint) last author

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