EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 428/3 Article
Free access article

Issue A&A
Volume 428, Number 3, December IV 2004
Page(s) 781 - 791
Section Cosmology (including clusters of galaxies)
DOI http://dx.doi.org/10.1051/0004-6361:20041182



A&A 428, 781-791 (2004)
DOI: 10.1051/0004-6361:20041182

Effects of thermal fluctuations in the SPOrt experiment

E. Carretti1, M. Zannoni2, C. Macculi1, S. Cortiglioni1 and C. Sbarra1

1  IASF/CNR Bologna, via Gobetti 101, 40129 Bologna, Italy
    e-mail: carretti@bo.iasf.cnr.it
2  IASF/CNR Milano, via Bassini 15, 20133 Milano, Italy

(Received 29 April 2004 / Accepted 20 August 2004)

Abstract
The role of systematic errors induced by thermal fluctuations is analyzed for the SPOrt experiment with the aim at estimating their impact on the measurement of the Cosmic Microwave Background Polarization (CMBP). The transfer functions of the antenna devices from temperature to data fluctuations are computed, by writing them in terms of both instrument and thermal environment parameters. In addition, the corresponding contamination maps are estimated, along with their polarized power spectra, for different behaviours of the instabilities. The result is that thermal effects are at a negligible level even for fluctuations correlated with the Sun illumination provided their frequency  $f_{\rm tf}$ is larger than that of the Sun illumination ( $f_{\rm day}$) by a factor  $f_{\rm tf} / f_{\rm day} > 30$, which defines a requirement for the statistical properties of the temperature behaviour. The analysis with actual SPOrt operative parameters shows that the instrument is only weakly sensitive to temperature instabilities, the main contribution coming from the cryogenic stage. The contamination on the E-mode spectrum does not significantly pollute the CMBP signal and no specific data cleaning seems to be needed.


Key words: polarization -- cosmology: cosmic microwave background -- instrumentation: polarimeters -- methods: data analysis




© ESO 2004


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.