Atomic data for astrophysics: Fe IX

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

Research output: Contribution to journalArticle

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Abstract

We present the results of a new large-scale intermediate-coupling frame transformation R-matrix scattering calculation for electron collisional excitation of Fe ix. The target includes all the main configurations up to n = 5, to improve our earlier R-matrix and distorted-wave (DW) calculations for the n = 3,4 levels. Unlike similar calculations which we carried out for the other coronal iron ions, in this case the larger target does not significantly affect the collision strengths of the strongest transitions to the n = 3,4 levels. Some differences are however present for a few transitions, in particular for the 3d–4p line at 197.86 Å. For the weaker transitions, significant enhancements due to extra resonances resulting from this much bigger target are found. Several new line identifications are suggested. We find excellent agreement between predicted and observed line intensities in the EUV (Hinode EIS) showing that Fe ix lines provide a reliable temperature diagnostic. We also show that the visible forbidden lines are a good diagnostic to measure electron densities.
Original languageEnglish
Article numberA77
Number of pages11
JournalAstronomy and Astrophysics
Volume565
Early online date14 May 2014
DOIs
Publication statusPublished - May 2014

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astrophysics
matrix
S matrix theory
electron density
collision
scattering
iron
electron
collisions
ion
augmentation
configurations
excitation
calculation
ions
electrons
temperature

Keywords

  • atomic data
  • atomic identification
  • FeIX

Cite this

Del Zanna, G. ; Storey, P.J. ; Badnell, N.R. ; Mason, H.E. . / Atomic data for astrophysics : Fe IX. In: Astronomy and Astrophysics. 2014 ; Vol. 565.
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Atomic data for astrophysics : Fe IX. / Del Zanna, G.; Storey, P.J.; Badnell, N.R.; Mason, H.E. .

In: Astronomy and Astrophysics, Vol. 565, A77, 05.2014.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Atomic data for astrophysics

T2 - Fe IX

AU - Del Zanna, G.

AU - Storey, P.J.

AU - Badnell, N.R.

AU - Mason, H.E.

PY - 2014/5

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AB - We present the results of a new large-scale intermediate-coupling frame transformation R-matrix scattering calculation for electron collisional excitation of Fe ix. The target includes all the main configurations up to n = 5, to improve our earlier R-matrix and distorted-wave (DW) calculations for the n = 3,4 levels. Unlike similar calculations which we carried out for the other coronal iron ions, in this case the larger target does not significantly affect the collision strengths of the strongest transitions to the n = 3,4 levels. Some differences are however present for a few transitions, in particular for the 3d–4p line at 197.86 Å. For the weaker transitions, significant enhancements due to extra resonances resulting from this much bigger target are found. Several new line identifications are suggested. We find excellent agreement between predicted and observed line intensities in the EUV (Hinode EIS) showing that Fe ix lines provide a reliable temperature diagnostic. We also show that the visible forbidden lines are a good diagnostic to measure electron densities.

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KW - atomic identification

KW - FeIX

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