GaBoDS: The garching-bonn deep survey. VII. Cosmic shear analysis

• Published in: Astronomy and astrophysics (Berlin) Vol. 468; no. 3; pp. 859 - 876
• Main Authors: HETTERSCHEIDT, M, SIMON, P, SCHIRMER, M, HILDEBRANDT, H, SCHRABBACK, T, ERBEN, T, SCHNEIDER, P
• Format: Journal Article
• Language: English
• Published: Les Ulis EDP Sciences 01.06.2007
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Data analysis; Red shift; Uncertainty; Shear; gravitational lensing- large-scale structure of the Universe; Power spectra; Gravitational lensing; Energy density; Correlation functions; Large-scale structure; Baryons; Markov chain; Cosmological parameter; Hubble constant; Cosmology; Dark energy; Mass spectra; N galaxies; cosmological parameters; Flat metric
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361:20065885

Aims. We present a cosmic shear analysis and data validation of 15 square degree high-quality R-band data of the Garching-Bonn Deep Survey obtained with the Wide Field Imager of the MPG/ESO 2.2 m telescope. Methods. We measure the two-point shear correlation functions to calculate the aperture mass dispersion. Both statistics are used to perform the data quality control. Combining the cosmic shear signal with a photometric redshift distribution of a galaxy sub-sample obtained from two square degree of UBVRI-band observations of the Deep Public Survey we determine constraints for the matter density \Omega_{\rm m}, the mass power spectrum normalisation \sigma_8 and the dark energy density \Omega_\Lambda in the magnitude interval R\in [21.5,24.5]. In this magnitude interval the effective number density of source galaxies is n=12.5\,{\rm arcmin} less than or equal to and their mean redshift is \bar z=0.78. To estimate the posterior likelihood we employ the Monte Carlo Markov Chain method. Results. Using the aperture mass dispersion we obtain for the mass power spectrum normalisation \sigma_8=0.80\pm 0.10 (1\sigma statistical error) at a fixed matter density \Omega_{\rm m}=0.30 assuming a flat universe with negligible baryon content and marginalising over the Hubble parameter and the uncertainties in the fitted redshift distribution.