2004/07/31 by Sébastien Bardeau, S. Bardeau, J. -P. Kneib +7 · 2 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1051/0004-6361:20041643
16 pages, 13 figures. Corrected typos, minor changes. Accepted by A&A
arxiv created 2005/02/10 · openalex publication_date 2005/04/11 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We describe the weak lensing methodology we have applied to multi-colour CFH12k imaging of a homogeneously-selected sample of luminous X-ray clusters at . The aim of our survey is to understand the variation in cluster structure and dark matter profile within rich clusters. The method we describe converts a fully reduced CFH12k image into constraints on the cluster mass distribution in two steps: (1) determination of the “true” shape of faint (lensed) galaxies, including object detection, point spread function (PSF) determination, galaxy shape measurement with errors; (2) conversion of the faint galaxy catalogue into reliable mass constraints using a range of 1D and 2D lensing techniques. Mass estimates are derived independently from each of the three images taken in separate filters to quantify the systematic uncertainties. Finally, we compare the cluster mass model to the light distribution of cluster members as derived from our imaging data. To illustrate the method, we apply it to the well-studied cluster Abell 1689 (). In this cluster, we detect the gravitational shear signal out to ~3 Mpc at >3-σ significance. The two-dimensional mass reconstruction has a ~10-σ significance peak centered on the brightest cluster galaxy. The weak lensing profile is well fitted by a NFW mass profile with , and (), or by a power law profile with ± 0.07 and ± (). The mass-to-light ratio is found to be almost constant with radius with a mean value of . We compare these results to other weak lensing analyses of Abell 1689 from the literature and find good agreements in terms of the shear measurement as well as the final mass estimate.