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Title: Laboratory measurements of the K-shell transition energies in L-shell ions of Si and S [Energy measurements of K-shell transitions in L-shell ions of Si and S]

We have measured the energies of the strongest 1s–2$${\ell }\ ({\ell }={\rm{s}},{\rm{p}})$$ transitions in He- through Ne-like silicon and sulfur ions to an accuracy of $$\lt 1\,\mathrm{eV}$$ using the Lawrence Livermore National Laboratory's electron beam ion traps, EBIT-I and SuperEBIT, and the NASA/GSFC EBIT Calorimeter Spectrometer (ECS). We identify and measure the energies of 18 and 21 X-ray features from silicon and sulfur, respectively. The results are compared to new Flexible Atomic Code calculations and to semi-relativistic Hartree–Fock calculations by Palmeri et al. (2008). These results will be especially useful for wind diagnostics in high-mass X-ray binaries, such as Vela X-1 and Cygnus X-1, where high-resolution spectral measurements using Chandra's high-energy transmission grating has made it possible to measure Doppler shifts of $$100\,\mathrm{km}\,{{\rm{s}}}^{-1}$$. The accuracy of our measurements is consistent with that needed to analyze Chandra observations, exceeding Chandra's $$100\,\mathrm{km}\,{{\rm{s}}}^{-1}$$ limit. Hence, the results presented here not only provide benchmarks for theory, but also accurate rest energies that can be used to determine the bulk motion of material in astrophysical sources. Finally, we show the usefulness of our results by applying them to redetermine Doppler shifts from Chandra observations of Vela X-1.
ORCiD logo [1] ;  [2] ; ORCiD logo [3] ; ORCiD logo [4] ;  [2] ;  [2] ;  [5] ;  [5] ;  [5] ; ORCiD logo [2]
  1. Univ. Erlangen-Numberg, Bamberg (Germany); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Univ. Erlangen-Numberg, Bamberg (Germany)
  4. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  5. NASA-GSFC, Greenbelt, MD (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 1538-4357; TRN: US1701579
Grant/Contract Number:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 830; Journal Issue: 1; Journal ID: ISSN 1538-4357
Institute of Physics (IOP)
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
Country of Publication:
United States
74 ATOMIC AND MOLECULAR PHYSICS; 79 ASTRONOMY AND ASTROPHYSICS; atomic date; methods: laboratory: atomic; X-rays: binaries; X-rays: general
OSTI Identifier: