The shear power spectrum from the COMBO-17 survey

2002/10/31 by M. L. Brown, A. N. Taylor, D. J. Bacon +4 · 8 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #COSMIC cancer database #Cosmic variance #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Galaxy #Matter power spectrum #Photometric redshift #Redshift #Redshift survey #Spectral density #Weak gravitational lensing #astro-ph

paper · pdf · doi:10.1046/j.1365-8711.2003.06237.x

published as Mon.Not.Roy.Astron.Soc.341:100,2003 · Matches version to appear in 1st May edition of MNRAS (vol. 341, pp.100-118)

arxiv created 2003/04/04 · openalex publication_date 2003/05/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

We perform a cosmic shear analysis of the COMBO-17 survey -- a unique dataset with shear quality R-band imaging and accurate photometric redshift estimates (dz=0.05) for ~90% of galaxies to R=24.0. We undertake a full maximum likelihood analysis to measure the weak lensing power spectra, Cl^kk, Cl^bb & Cl^kb from l=400 to l=10⁴. We find a strong measurement of the convergence power over five fields. The b-field has a much lower significance, indicating our data is free of major systematics, while the cross-correlation of k & b is consistent with zero. We have also calculated the shear correlation functions and variance over a range of scales between 0.5 and 20 arcmin. In addition, we have used our results to measure cosmological parameters, constraining the normalisation of the matter power spectrum to be sigma₈=(0.72 ± 0.09)(Omega_m/0.3)^-0.49, where the errors quoted are 1-sigma due to the intrinsic dispersion in galaxy ellipticities, cosmic and sampling variance. We have significantly reduced the usual additional uncertainty in the median redshift (z_m) of the survey by estimating z_m directly from the data. To demonstrate the power of accurate redshift information, we have also measured parameters from a shear analysis of only those galaxies with accurate redshifts. In this case, we have eliminated the uncertainty in the redshift distribution of sources and we show that the uncertainty in the resulting parameter constraints are reduced by more than a factor of 2 compared to the typical uncertainties found in cosmic shear surveys to date. Finally, we combine our parameter measurements with constraints from the 2dFGRS and from the CMB. With these additional constraints, we measure sigma₈=0.73 +0.05/-0.03 and Omega_m=0.27 +/- 0.02.

Citations

• Measuring Ωmwith theROSATDeep Cluster Survey
• Gravitational Lens Magnification and the Mass of Abell 1689
• Multiple Peaks in the Angular Power Spectrum of the Cosmic Microwave Background: Significance and Consequences for Cosmology
• Detection of Weak Lensing by a Cluster of Galaxies atz= 0.83
• Final Results from theHubble Space TelescopeKey Project to Measure the Hubble Constant
• Weak gravitational lensing: reducing the contamination by intrinsic alignments
• The redshift and scale dependence of the cosmic shear signal from numerical simulations
• Probing the Universe with Weak Lensing
• Power Spectrum Covariance of Weak Gravitational Lensing
• Shapelets -- II. A method for weak lensing measurements
• On the density of Cold Dark Matter

Cited by

• 3D cosmic shear: cosmology from CFHTLenS
• The intrinsic alignment of galaxies and its impact on weak gravitational lensing in an era of precision cosmology
• Reconstruction of the One‐Point Distribution of Convergence from Weak Lensing by Large‐Scale Structure
• Detection of large-scale intrinsic ellipticity--density correlation from the Sloan Digital Sky Survey and implications for weak lensing surveys
• Cosmic shear analysis of archival HST/ACS data
• Cosmology and the bispectrum
• Power spectrum normalization and the non-Gaussian halo model
• Photometric Redshift Biases from Galaxy Evolution