Astronomy & Astrophysics

A&A 447, 761-768 (2006)
DOI: 10.1051/0004-6361:20042511

Benchmarking atomic data for astrophysics: $\ion{xxiv}$

G. Del Zanna

University College London, MSSL, Holmbury St. Mary Dorking Surrey RH5 6NT, UK
e-mail: gdz@mssl.ucl.ac.uk

(Received 9 December 2004 / Accepted 11 October 2005)

Abstract
Fe XXIV produces strong L-shell ( $n=3,\,4,\,5 \to 2$ ) spectral lines in the X-rays. These lines have been observed in solar flares, in laboratory spectra, and in a variety of astrophysical sources with e.g. the Chandra and XMM-Newton satellites. In this paper atomic data for Fe XXIV L-shell emission are benchmarked against experimental data. The work focuses on reviewing and assessing previous line identifications on a quantitative basis, paying particular attention to the most important lines for laboratory and astrophysical applications. Previous identifications are confirmed, but many lines turn out to be significantly blended. The agreement between theoretical and observed data in terms of wavelengths, line intensities and level lifetimes is good, within the experimental uncertainties. Fe XXIV L-shell lines can be used to measure electron densities in laboratory plasmas and temperatures for a wide range of astrophysical sources.

Key words: atomic data -- line: identification -- Sun: flares -- techniques: spectroscopic

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