Atomic data for astrophysics: Fe X soft x-ray lines

G. Del Zanna, P. J. Storey, N. R. Badnell, H. E. Mason

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

New atomic calculations for Fe x are presented. They focus on the need to model the soft X-ray spectrum and in particular the line at 94.0 Å which is the dominant contribution to the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) 94 Å band in quiet Sun conditions. This line, and others in the band, are due to strong decays from n = 4 levels. We present new large-scale R-matrix (up to n = 4) and distorted-wave (DW, up to n = 6) scattering calculations for electron collisional excitation and compare them to earlier work. We find significant discrepancies with previous calculations. We show that resonances significantly increase the cross-sections for excitations from the ground state to some n = 4 levels, in particular to those in the 3s2 3p4 4s configuration. Cascading from higher levels is also important. We suggest a new identification for the 3s 3p62S1/2–3s 3p5 4s 2P3/2 transition, that has a predicted intensity larger than the decays from the 3s2 3p4 4s levels which were identified by Edlén in 1936. The results presented here are relevant to our understanding of transitions from n = 4 levels in a wide range of other ions.
LanguageEnglish
Article numberA90
Number of pages10
JournalAstronomy and Astrophysics
Volume541
DOIs
Publication statusPublished - 1 May 2012

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astrophysics
x rays
observatory
cross section
helioseismology
scattering
decay
electron
matrix
ion
excitation
observatories
sun
assembly
calculation
ground state
cross sections
configurations
ions
electrons

Keywords

  • atomic data
  • identification
  • corona
  • spectroscopic

Cite this

Del Zanna, G. ; Storey, P. J. ; Badnell, N. R. ; Mason, H. E. / Atomic data for astrophysics : Fe X soft x-ray lines. In: Astronomy and Astrophysics. 2012 ; Vol. 541.
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abstract = "New atomic calculations for Fe x are presented. They focus on the need to model the soft X-ray spectrum and in particular the line at 94.0 {\AA} which is the dominant contribution to the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) 94 {\AA} band in quiet Sun conditions. This line, and others in the band, are due to strong decays from n = 4 levels. We present new large-scale R-matrix (up to n = 4) and distorted-wave (DW, up to n = 6) scattering calculations for electron collisional excitation and compare them to earlier work. We find significant discrepancies with previous calculations. We show that resonances significantly increase the cross-sections for excitations from the ground state to some n = 4 levels, in particular to those in the 3s2 3p4 4s configuration. Cascading from higher levels is also important. We suggest a new identification for the 3s 3p62S1/2–3s 3p5 4s 2P3/2 transition, that has a predicted intensity larger than the decays from the 3s2 3p4 4s levels which were identified by Edl{\'e}n in 1936. The results presented here are relevant to our understanding of transitions from n = 4 levels in a wide range of other ions.",
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Atomic data for astrophysics : Fe X soft x-ray lines. / Del Zanna, G.; Storey, P. J.; Badnell, N. R.; Mason, H. E.

In: Astronomy and Astrophysics, Vol. 541, A90, 01.05.2012.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Atomic data for astrophysics

T2 - Astronomy and Astrophysics

AU - Del Zanna, G.

AU - Storey, P. J.

AU - Badnell, N. R.

AU - Mason, H. E.

N1 - Reproduced with permission from Astronomy & Astrophysics, © ESO 2012.

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AB - New atomic calculations for Fe x are presented. They focus on the need to model the soft X-ray spectrum and in particular the line at 94.0 Å which is the dominant contribution to the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) 94 Å band in quiet Sun conditions. This line, and others in the band, are due to strong decays from n = 4 levels. We present new large-scale R-matrix (up to n = 4) and distorted-wave (DW, up to n = 6) scattering calculations for electron collisional excitation and compare them to earlier work. We find significant discrepancies with previous calculations. We show that resonances significantly increase the cross-sections for excitations from the ground state to some n = 4 levels, in particular to those in the 3s2 3p4 4s configuration. Cascading from higher levels is also important. We suggest a new identification for the 3s 3p62S1/2–3s 3p5 4s 2P3/2 transition, that has a predicted intensity larger than the decays from the 3s2 3p4 4s levels which were identified by Edlén in 1936. The results presented here are relevant to our understanding of transitions from n = 4 levels in a wide range of other ions.

KW - atomic data

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KW - corona

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