EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 373/3 Article
Free access article

Issue A&A
Volume 373, Number 3, July III 2001
Page(s) 836 - 842
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20010628



A&A 373, 836-842 (2001)
DOI: 10.1051/0004-6361:20010628

Argon, silicon and iron abundances in the damped Ly-$\alpha$ system I Zw 18

S. A. Levshakov1, W. H. Kegel2 and I. I. Agafonova1

1  Department of Theoretical Astrophysics, Ioffe Physico-Technical Institute, 194021 St. Petersburg, Russia
    e-mail: lev@astro.ioffe.rssi.ru
    e-mail: ira@astro.ioffe.rssi.ru
2  Insitut für Theoretische Physik der Universität Frankfurt am Main, 60054 Frankfurt/Main 11, Germany
    e-mail: kegel@astro.uni-frankfurt.de

(Received 28 November 2000 / Accepted 1 May 2001)

Abstract
We show how the ratio of the abundances of Ar, Si and Fe as derived from FUSE absorption spectra of I Zw 18 are affected by large-scale stochastic velocity fields (mesoturbulence). 21-cm observations with high spatial resolution show the presence of velocity fields with large correlation lengths. FUSE observations were performed with a large entrance aperture which fully covered the galaxy. This means that the observed profiles are averaged over the full body of I Zw 18. Taking this into account, we show that the observations are consistent with the abundance ratios [ $\alpha$-chain/Fe] being similar to those derived from Galactic metal-poor stars. Using a mesoturbulent approach, we found that the observed profiles can be reproduced well with [Fe/H] $=-2.4\pm0.1$, and [Si, Ar/Fe] $= 0.7\pm0.1$.


Key words: line: formation -- line: profiles -- galaxies: individual: I Zw 18

Offprint request: S. A. Levshakov, sergei@oat.ts.astro.it

SIMBAD Objects



© ESO 2001


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.