X-ray spectra of the Fe-L complex

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Gu, Liyi and Raassen, A. J. J. and Mao, Junjie and Plaa, Jelle de and Shah, Chintan and Pinto, Ciro and Werner, Norbert and Simionescu, Aurora and Mernier, François and Kaastra, Jelle S. (2019) X-ray spectra of the Fe-L complex. Astronomy and Astrophysics, 627. ISSN 0004-6361 (https://doi.org/10.1051/0004-6361/201833860)

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Abstract

The Hitomi results on the Perseus cluster lead to improvements in our knowledge of atomic physics which are crucial for the precise diagnostic of hot astrophysical plasma observed with high-resolution X-ray spectrometers. However, modeling uncertainties remain, both within but especially beyond Hitomi's spectral window. A major challenge in spectral modeling is the Fe-L spectrum, which is basically a complex assembly of n>2 to n=2 transitions of Fe ions in different ionization states, affected by a range of atomic processes such as collisional excitation, resonant excitation, radiative recombination, dielectronic recombination, and innershell ionization. In this paper we perform a large-scale theoretical calculation on each of the processes with the flexible atomic code (FAC), focusing on ions of Fe XVII to Fe XXIV that form the main body of the Fe-L complex. The new data are found to be consistent within 20% with the recent individual R-matrix calculations for the main Fe-L lines. By further testing the new FAC calculations with the high-quality RGS data from 15 elliptical galaxies and galaxy clusters, we note that the new model gives systematically better fits than the current SPEX v3.04 code, and the mean Fe abundance decreases by 12%, while the O/Fe ratio increases by 16% compared with the results from the current code. Comparing the FAC fit results to those with the R-matrix calculations, we find a temperature-dependent discrepancy of up to ~10% on the Fe abundance between the two theoretical models. Further dedicated tests with both observed spectra and targeted laboratory measurements are needed to resolve the discrepancies, and ultimately, to get the atomic data ready for the next high-resolution X-ray spectroscopy mission.

ORCID iDs

Gu, Liyi, Raassen, A. J. J., Mao, Junjie ORCID logoORCID: https://orcid.org/0000-0001-7557-9713, Plaa, Jelle de, Shah, Chintan, Pinto, Ciro, Werner, Norbert, Simionescu, Aurora, Mernier, François and Kaastra, Jelle S.;
  • Item type:Article
    ID code:68897
    Dates:
    Date
    Event
    31 July 2019
    Published
    1 July 2019
    Published Online
    19 May 2019
    Accepted
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:17 Jul 2019 14:40
    Last modified:11 Nov 2024 12:22
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/68897
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