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

Zanna, G. Del; Storey, P. J.

doi:10.1051/0004-6361/201219835

Cited by 25 publications

(23 citation statements)

References 25 publications

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“…The effect is notable for the 3s 2 3p 5 4s levels because they have small collision strengths from the ground configuration. However, similar issues have been found for other Fe ix configurations in our recent large-scale R-matrix calculation , but also in general with all other coronal iron ions: Fe x , Fe xi (Del Zanna & Storey 2013), Fe xii , and Fe xiii (Del Zanna & Storey 2013).…”

Section: Introductionsupporting

confidence: 85%

Atomic data for astrophysics: Ni XI

Zanna¹,

Storey

Badnell

2014

A&A

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We present a new large-scale R-matrix scattering calculation for electron collisional excitation of Ni xi, carried out with the intermediate-coupling frame transformation method. The target includes all the main configurations up to n = 4, and is a significant improvement over earlier R-matrix (only three n = 3 configurations) and distorted-wave (DW) calculations. We find significant enhancements in the collision strengths of many of the strong transitions to the n = 3, 4 levels. They are due to the resonances that arise within the present large-scale target. This results in significant increases in the predicted intensities of the UV and visible forbidden lines within the 3s 2 3p 5 3d configuration, the strong EUV lines that result from the decays of the 3s 2 3p 5 3d levels to the ground state, and the decays from the n = 4 levels, which are visible in the soft X-rays. We find good agreement between predicted and observed line intensities in the EUV. With the present atomic data, lines from Ni xi can reliably be used for plasma diagnostics. We also revise some level energies and suggest a few new possible identifications.

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Section: Introductionsupporting

confidence: 85%

Atomic data for astrophysics: Ni XI

Zanna¹,

Storey

Badnell

2014

A&A

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“…We have seen similar increases in Fe xiii, which are due to the effect of the resonances (Del Zanna & Storey 2013). For example, Fig.…”

Section: The Soft X-ray Linessupporting

confidence: 63%

Atomic data for astrophysics: Ni XV

Zanna¹,

Storey²,

Mason³

2014

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We present the first R-matrix scattering calculation for electron collisional excitation of Ni xv. The large-scale target includes configurations up to n = 4. The calculations were carried out using the intermediate-coupling frame transformation method. Significant enhancements in the collision strengths, compared to previous distorted-wave (DW) calculations, are found for several cases, in particular the forbidden lines within the ground configuration and the 3s 2 3p 4s levels. We provide a complete set of rates and a list of strongest lines that are observable in astrophysical plasmas. Previous identifications are reviewed, and a few new ones suggested. The new data can be used to accurately measure electron densities for high-temperature (3 MK) plasmas, and the nickel abundance.

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“…The accuracy was confirmed a posteriori with detailed comparisons against observations (Del Zanna 2010). Later, we performed a larger scattering calculation (Del Zanna & Storey 2013), which significantly improved the atomic data for many lower (within the n = 3) and higher (n = 4) levels, but did not produce accurate collision strengths for these three n = 3, J = 1 levels.…”

Section: Discussionmentioning

confidence: 99%

Atomic data for astrophysics: improved collision strengths for Fe viii

Zanna¹,

Badnell

2014

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We describe, and present the results of, a new large-scale R-matrix scattering calculation for the electron collisional excitation of Fe viii. We first discuss the limitations of the previous calculations, in particular concerning some strong EUV lines observed in the solar corona by the Hinode EUV Imaging Spectrometer. We then present a new target which represents an improvement over the previous ones for this particularly complex ion. We developed a new method, based on the use of term energy corrections within the intermediate coupling frame transformation method, to calculate the collision strengths. We compare predicted and observed line intensities using laboratory and solar spectra, finding excellent agreement for all the main soft X-ray and extreme ultraviolet (EUV) transitions, using the present atomic data. In particular, we show that Fe viii EUV lines observed by Hinode EIS can now be used to provide reliable electron temperatures for the solar corona.

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

Cited by 25 publications

References 25 publications

Atomic data for astrophysics: Ni XI

Atomic data for astrophysics: Ni XI

Atomic data for astrophysics: Ni XV

Atomic data for astrophysics: improved collision strengths for Fe viii

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