### Abstract

Original language | English |
---|---|

Article number | A139 |

Number of pages | 10 |

Journal | Astronomy and Astrophysics |

Volume | 543 |

DOIs | |

Publication status | Published - 12 Jul 2012 |

### Fingerprint

### Keywords

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

### Cite this

*Astronomy and Astrophysics*,

*543*, [A139]. https://doi.org/10.1051/0004-6361/201219023

}

*Astronomy and Astrophysics*, vol. 543, A139. https://doi.org/10.1051/0004-6361/201219023

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

Research output: Contribution to journal › Article

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 -