Benchmarking atomic data for astrophysics: Fe xi

Zanna, G. Del

doi:10.1051/0004-6361/201014063

Cited by 40 publications

(23 citation statements)

References 40 publications

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“…A few important temperature diagnostics for Hinode/EIS were discussed in Del Zanna (2009a,b and2010) and have not been repeated here. The various calibration problems for the Hinode/EIS instrument, highlighted here, will need to be properly assessed before these new temperature diagnostics can be used reliably.…”

Section: Discussionmentioning

confidence: 99%

Benchmarking atomic data for the CHIANTI atomic database: coronal lines observed by Hinode EIS

Zanna¹

2012

A&A

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The coronal lines that are observable in the Hinode EUV Imaging Spectrometer (EIS) wavelengths are assessed with new atomic data that have recently become available for a range of important ions. EIS spectral lines are identified based on their spatial variation across different solar regions, their wavelengths, and their intensities. Two off-limb observations are presented, one above an active region, and one in the quiet Sun. The spectra are relatively free of low-temperature lines. Accurate wavelengths and intensities are provided. The observed and predicted line intensities generally agree excellently, once blending is taken into account. The main diagnostics available for measuring the electron density of the solar corona using EIS are highlighted with the use of the emissivity ratio technique. Densities obtained from different ions agree excellently. Most of the previous identifications are confirmed. A considerable number of weaker lines still await identification, however. The approximate formation temperature of the main unidentified lines is provided to aid the identification process. The EIS radiometric calibration appears to be in need of revision. A new quiet-Sun argon/iron relative abundance of 0.16, in line with Galactic measurements, is found. The abundances of sulphur and argon in the "background" unresolved active region emission are found to be lower by a factor of about two at 1.5 MK, and even lower at 3 MK.

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Section: Discussionmentioning

confidence: 99%

Benchmarking atomic data for the CHIANTI atomic database: coronal lines observed by Hinode EIS

Zanna¹

2012

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“…The previous identifications are due to Edlén (1937b) and Fawcett. The energies of the lower n = 3 levels have been carefully assessed in Del Zanna (2010) and are adopted here. Fig.…”

Section: Fe XImentioning

confidence: 99%

Benchmarking atomic data for astrophysics: a first look at the soft X-ray lines

Zanna¹

2012

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A collection of the best solar and laboratory spectra in the soft X-rays is used here to perform a preliminary benchmark in this wavelength region, by comparing observed vs. predicted wavelengths and calibrated solar irradiances. The benchmark focuses on the Fe ix -Fe xiv ions, for which we have recently calculated the relevant atomic data, however a few other ions have also been benchmarked. The iron ions are dominating the soft X-rays, however a large fraction of the strongest soft X-ray lines due to n = 4 → n = 3 transitions were previously unidentified. The strongest transitions are all identified here, in particular the decays from the core-excited levels (3s 3p l 4s, l = 5,4,3,2,1 for Fe x, Fe xi, Fe xii, Fe xiii, and Fe xiv respectively) which are the strongest soft X-ray transitions from these ions. Many new identifications are proposed, some only tentatively. Good agreement in terms of solar irradiances between the soft-Xray and EUV (n = 3 → n = 3) transitions is found, confirming the reliability of the new large-scale calculations. Some of the new atomic data and identifications are particularly important for the Solar Dynamic Observatory (SDO) Atmospheric Imaging Assembly (AIA) 94 Å band.

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“…Keenan et al (2005) incorrectly identified the 2-39, 3-39 transitions with the lines observed at 189.19 and 189.72 Å respectively. (Del Zanna 2010) are shown, together with those obtained from our scattering target E target , those from our benchmark E bench , those from our benchmark including TEC E bench (TEC). We also list the values from the NIST compilation (E NIST ) and those calculated with the many-body perturbation theory (E MR−MP ) by Ishikawa & Vilkas (2008).…”

Section: Our Targetmentioning

confidence: 99%

Atomic data from the IRON project

Zanna¹,

Storey

Mason³

2010

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A new R-matrix scattering calculation for electron collisional excitation of Fe xi is presented and compared to earlier calculations.The calculation includes 145 LS terms and 465 fine-structure levels and uses the intermediate-coupling frame transformation method (ICFT). We discuss the strong interactions that exist between three J = 1 levels in the 3s 2 3p 3 3d electron configuration. These levels give rise to strong lines in the EUV spectrum and their energies and identifications have been the source of much confusion in the literature. We show that the oscillator and collision strengths linking these levels to the ground levels of the ion are very sensitive to the choice of configuration basis and argue that most earlier calculations have failed to represent these levels adequately.

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Benchmarking atomic data for astrophysics: Fe xi

Cited by 40 publications

References 40 publications

Benchmarking atomic data for the CHIANTI atomic database: coronal lines observed by Hinode EIS

Benchmarking atomic data for the CHIANTI atomic database: coronal lines observed by Hinode EIS

Benchmarking atomic data for astrophysics: a first look at the soft X-ray lines

Atomic data from the IRON project

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