EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 403/ 2 Article

Free access article

Issue A&A
Volume 403, Number 2, May IV 2003
Page(s) 725 - 730
Section Diffuse matter in space
DOI http://dx.doi.org/10.1051/0004-6361:20030400



A&A 403, 725-730 (2003)
DOI: 10.1051/0004-6361:20030400

Variability of EUV-spectra from the quiet upper solar atmosphere: Intensity and Doppler shift

A. Brkovic1, 2, H. Peter1 and S. K. Solanki3

1  Kiepenheuer-Institut für Sonnenphysik, Schöneckstr. 6, 79104 Freiburg, Germany
2  Institute of Astronomy, ETH-Zentrum, 8092 Zürich, Switzerland
3  Max-Planck-Institut für Aeronomie, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany

(Received 15 May 2002 / Accepted 11 March 2003 )

Abstract
We have studied SUMER and CDS time series of spectra and images of quiet-Sun regions at the solar disc centre. The data contain ultraviolet emission lines sampling temperatures of the chromosphere, transition region and corona. We find a high correlation between average net Doppler shifts and relative brightness variabilities of the studied lines (correlation coefficient of  0.92), suggesting a connection between the two quantities. The anti-correlation between differential emission measures and relative brightness variabilities is weaker (correlation coefficient of -0.78). We discuss the observed relationships on the basis of differential emission measures and linear wave calculations.


Key words: Sun: chromosphere -- Sun: corona -- Sun: transition region -- Sun: UV radiation

Offprint request: A. Brkovic, alen@kis.uni-freiburg.de




© ESO 2003

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.