An astrophysical oscillator strength for the SII 94.7 nm resonance line and S abundances in DLAs

Abstract

By using UV spectra for the O star HD 93521 taken with the ORFEUS II echelle spectrograph, we determine an ``astrophysical'' f value for the SII 94.7 nm line: f = 0.00498 (+0.00172)(-0.00138), error at 1 sigma level.This is almost a factor of 30 smaller than the guessed value found in the Kurucz database (f=0.1472), which was up to now the only one available for this transition. We use our ``astrophysical'' f to investigate the S abundance in two Damped Ly-alpha absorption systems (DLAs) observed with UVES at the ESO 8.2m Kueyen telescope. In the case of the absorber at zabs=3.02486 towards QSO 0347-3819 we find a sulphur column density which is consistent, within errors, with that determined by Centurion et al by means of the 125.9 nm line, thus providing an external check on the accuracy of our f value. For the damped absorber at zabs=4.4680 towards BR J0307-4945 we determine a high value of the S abundance, which, however, is probably the result of blending with Ly-alpha forest lines.

arXiv commentAccepted by MNRAS

References in corpus (5)

• Chemical Abundances of the Damped Lya Systems at z>1.5
• Diffraction-limited 800nm imaging with the 2.56m Nordic Optical Telescope
• Chemical Evolution of Damped Ly alpha galaxies: The [S/Zn] abundance ratio at redshift z > 2
• UVES observations of a damped Ly-alpha system at z_abs = 4.466 towards the quasar APM BR J0307-4945
• Nitrogen Abundances in Damped Ly alpha Galaxies

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• VLT/UVES observations of peculiar alpha abundances in a sub-DLA at z ~ 1.8 towards the quasar B1101-26