EDP Sciences
Free access
Issue A&A
Volume 487, Number 3, September I 2008
Page(s) 1203 - 1208
Section Atomic, molecular, and nuclear data
DOI http://dx.doi.org/10.1051/0004-6361:200809998
Published online 24 June 2008



A&A 487, 1203-1208 (2008)
DOI: 10.1051/0004-6361:200809998

Electron-impact excitation of Be-like Mg

G. Del Zanna1, 2, I. Rozum1, and N. R. Badnell3

1  MSSL, University College London, Holmbury St., Mary, Dorking RH5 6NT, UK
    e-mail: G.Del-Zanna@damtp.cam.ac.uk;GDelZanna@spd.aas.org
2  DAMTP, Centre for Mathematical Sciences, Wilberforce road, Cambridge CB3 0WA, UK
3  Department of Physics, University of Strathclyde, Glasgow G4 0NG, UK

Received 17 April 2008 / Accepted 13 June 2008

Abstract
We present an R-matrix calculation of electron-impact excitation of Be-like Mg. The calculation is similar to that one presented for Be-like Fe by Chidichimo et al. (2005, A&A, 430, 331), and was done with the intermediate-coupling frame transformation method and including a total of 98 fine-structure levels, up to n=4. We find significant differences with the widely used n=2 excitation rates of Keenan et al. (1986, Phys. Scr., 34, 216), calculated by interpolating R-matrix calculations along the Be-like sequence. We present a list of the most important transitions and a few comparisons with SOHO SUMER and CDS/GIS spectra of the solar corona. We show that previous long-standing discrepancies between observed and predicted line intensities are now resolved. We also show how temperatures of the solar corona were significantly underestimated. For example, a coronal hole inter-plume temperature of 850 000 K found by Wilhelm et al. (1998, ApJ, 500, 1023) is now revised to 1 160 000 K.


Key words: atomic data -- techniques: spectroscopic -- Sun: corona



© ESO 2008

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.

Editor-in-Chief: T. Forveille
Letters Editor-in-Chief: J. Alves
Managing Editor: C. Bertout

ISSN: 0004-6361 ; e-ISSN: 1432-0746
Frequency: 12 volumes per year
Published by: EDP Sciences

Mirror sites: CDS | EDP Sciences
  RSS feeds
© The European Southern Observatory (ESO)