1999/11/06 by Henk Hoekstra, Marijn Franx, Hoekstra, Henk +3
Chemistry · Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Spectroscopy and Laser Applications #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9911106
4 pages, 1 figure; to appear in "Gravitational Lensing: Recent Progress and Future Goals" ASP conference series, eds. Brainerd T. & Kochanek C. S
arxiv created 1999/11/06 · openalex publication_date 1999/11/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We have measured for the first time the weak lensing signal due to groups of galaxies. The groups are at intermediate redshifts, and have been identified in the CNOC2 field survey, which was kindly made available by Ray Carlberg and Howard Yee. The ensemble averaged group velocity dispersion, based on a preliminary selection of 59 groups, is found to be sigma= 320+46-54 km/s, which is in fair agreement with the dynamical estimate from the spectroscopic redshifts. Under the assumption that mass traces light, we find an average mass-to-light ratio in restframe B of (256±84)h Msun/Lsun. Using this result we obtain Omegam=0.22+-0.09 (ΩΛ=0).