Atomic data for the astrophysics

Fe XII soft X-ray lines.

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

Research output: Contribution to journalArticle

32 Citations (Scopus)
51 Downloads (Pure)

Abstract

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 of Fe xii. The first aim is to provide accurate atomic data for the soft X-rays, where strong decays from the n = 4 levels are present. As found in previous work on Fe x, resonances attached to n = 4 levels increase the cross-sections for excitations from the ground state to some n = 4 levels, when compared to DW calculations. Cascading from higher levels is also important. We provide a number of models and line intensities, and list a number of strong unidentified lines. The second aim is to assess the effects of the large R-matrix calculation on the n = 3 transitions. Compared to our previous (n = 3) R-matrix calculation, we find overall excellent agreement to within a few percent, however a few key density diagnostic EUV intensities differ by about 60% at coronal densities. The new atomic data result in lower electron densities, resolving previous discrepancies with solar observations.
Original languageEnglish
Article numberA139
Number of pages10
JournalAstronomy and Astrophysics
Volume543
DOIs
Publication statusPublished - 12 Jul 2012

Fingerprint

astrophysics
matrix
x rays
lists
electron density
excitation
cross section
scattering
electron
ground state
calculation
cross sections
decay
electrons

Keywords

  • atomic data
  • identification line
  • spectroscopic techniques
  • sun
  • corona
  • Fe xii
  • electron collisional excitation
  • coronal densities
  • extreme ultraviolet lines

Cite this

Del Zanna, G. ; Storey, P. J. ; Badnell, N. R. ; Mason, H.E. / Atomic data for the astrophysics : Fe XII soft X-ray lines. In: Astronomy and Astrophysics. 2012 ; Vol. 543.
@article{a6a9c3871f2f4146a18779aa3dd87d8f,
title = "Atomic data for the astrophysics: Fe XII soft X-ray lines.",
abstract = "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 of Fe xii. The first aim is to provide accurate atomic data for the soft X-rays, where strong decays from the n = 4 levels are present. As found in previous work on Fe x, resonances attached to n = 4 levels increase the cross-sections for excitations from the ground state to some n = 4 levels, when compared to DW calculations. Cascading from higher levels is also important. We provide a number of models and line intensities, and list a number of strong unidentified lines. The second aim is to assess the effects of the large R-matrix calculation on the n = 3 transitions. Compared to our previous (n = 3) R-matrix calculation, we find overall excellent agreement to within a few percent, however a few key density diagnostic EUV intensities differ by about 60{\%} at coronal densities. The new atomic data result in lower electron densities, resolving previous discrepancies with solar observations.",
keywords = "atomic data, identification line, spectroscopic techniques, sun, corona, Fe xii, electron collisional excitation, coronal densities, extreme ultraviolet lines",
author = "{Del Zanna}, G. and Storey, {P. J.} and Badnell, {N. R.} and H.E. Mason",
note = "Reproduced with permission from Astronomy & Astrophysics, {\circledC} ESO",
year = "2012",
month = "7",
day = "12",
doi = "10.1051/0004-6361/201219023",
language = "English",
volume = "543",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",

}

Atomic data for the astrophysics : Fe XII soft X-ray lines. / Del Zanna, G.; Storey, P. J.; Badnell, N. R.; Mason, H.E.

In: Astronomy and Astrophysics, Vol. 543, A139, 12.07.2012.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Atomic data for the astrophysics

T2 - Fe XII soft X-ray lines.

AU - Del Zanna, G.

AU - Storey, P. J.

AU - Badnell, N. R.

AU - Mason, H.E.

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

PY - 2012/7/12

Y1 - 2012/7/12

N2 - 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 of Fe xii. The first aim is to provide accurate atomic data for the soft X-rays, where strong decays from the n = 4 levels are present. As found in previous work on Fe x, resonances attached to n = 4 levels increase the cross-sections for excitations from the ground state to some n = 4 levels, when compared to DW calculations. Cascading from higher levels is also important. We provide a number of models and line intensities, and list a number of strong unidentified lines. The second aim is to assess the effects of the large R-matrix calculation on the n = 3 transitions. Compared to our previous (n = 3) R-matrix calculation, we find overall excellent agreement to within a few percent, however a few key density diagnostic EUV intensities differ by about 60% at coronal densities. The new atomic data result in lower electron densities, resolving previous discrepancies with solar observations.

AB - 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 of Fe xii. The first aim is to provide accurate atomic data for the soft X-rays, where strong decays from the n = 4 levels are present. As found in previous work on Fe x, resonances attached to n = 4 levels increase the cross-sections for excitations from the ground state to some n = 4 levels, when compared to DW calculations. Cascading from higher levels is also important. We provide a number of models and line intensities, and list a number of strong unidentified lines. The second aim is to assess the effects of the large R-matrix calculation on the n = 3 transitions. Compared to our previous (n = 3) R-matrix calculation, we find overall excellent agreement to within a few percent, however a few key density diagnostic EUV intensities differ by about 60% at coronal densities. The new atomic data result in lower electron densities, resolving previous discrepancies with solar observations.

KW - atomic data

KW - identification line

KW - spectroscopic techniques

KW - sun

KW - corona

KW - Fe xii

KW - electron collisional excitation

KW - coronal densities

KW - extreme ultraviolet lines

UR - http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/543/A139

UR - http://www.aanda.org/

U2 - 10.1051/0004-6361/201219023

DO - 10.1051/0004-6361/201219023

M3 - Article

VL - 543

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

M1 - A139

ER -