EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 368/3 Article
Free access article

Issue A&A
Volume 368, Number 3, March IV 2001
Page(s) 766 - 775
Section Cosmology
DOI http://dx.doi.org/10.1051/0004-6361:20010058



A&A 368, 766-775 (2001)
DOI: 10.1051/0004-6361:20010058

Cosmic shear analysis in 50 uncorrelated VLT fields. Implications for $\Omega_0$, $\sigma_8$

R. Maoli1, 2, 3, L. Van Waerbeke1, 4, Y. Mellier1, 2, P. Schneider5, B. Jain6, F. Bernardeau7, T. Erben8, 1, 2 and B. Fort1

1  Institut d'Astrophysique de Paris, 98bis boulevard Arago, 75014 Paris, France
2  Observatoire de Paris, DEMIRM, 61 avenue de l'Observatoire, 75014 Paris, France
3  Universitá "La Sapienza", P.le Aldo Moro 2, 00185 Roma, Italy
4  Canadian Institute for Theoretical Astrophysics, 60 St George Street, Toronto, M5S 3H8 Ontario, Canada
5  Institut für Astrophysik und Extraterrestrische Forschung der Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
6  Dept. of Physics, Johns Hopkins University, Baltimore, MD 21218, USA
7  Service de Physique Théorique, C.E. de Saclay, 91191 Gif-sur-Yvette Cedex, France
8  Max Planck Institut fur Astrophysiks, Karl-Schwarzschild-Str. 1, Postfach 1523, 85740 Garching, Germany

(Received 14 November 2000 / Accepted 8 January 2001 )

Abstract
We observed with the camera FORS1 on the VLT (UT1, ANTU) 50 randomly selected fields and analyzed the cosmic shear inside circular apertures with diameter ranging from 0.5 to 5.0 arcmin. The images were obtained in optimal conditions using the Service Observing proposed by ESO on the VLT, which enabled us to a well-defined and homogeneous set of data. The 50 fields cover a 0.64 square-degrees area spread over more than 1000 square-degrees obtain which provides a sample ideal for minimizing the cosmic variance. Using the same techniques as in Van Waerbeke et al. (2000), we measured the cosmic shear signal and investigated the systematics of the VLT sample. We find a significant excess of correlations between galaxy ellipticities on those angular scales. The amplitude and the shape of the correlation as function of angular scale are remarkably similar to those reported so far. Using our combined VLT and CFHT data and adding the results published by other teams we put the first joint constraints on $\Omega_0$ and $\sigma_8$ using cosmic shear surveys. From a deduced average of the redshift of the sources the combined data are consistent with $\sigma_8\simeq 0.59 ^{+0.03}_{-0.03} \Omega_0^{-0.47}$ (for a CDM power spectrum and $\Gamma=0.21$), in excellent agreement with the cosmological constraints obtained from the local cluster abundance. This is consistent with theoretical expectations if the density field grew from initial Gaussian conditions.


Key words: cosmology: theory -- cosmology: dark matter -- cosmology: gravitational lenses -- cosmology: large-scale structure of the Universe

Offprint request: Y. Mellier, mellier@iap.fr

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.