A Measurement of Weak Lensing by Large-Scale Structure in Red-Sequence Cluster Survey Fields
Abstract
We have analyzed ~24 deg2 of RC-band imaging data from the Red-Sequence Cluster Survey (RCS) and measured the excess correlations between galaxy ellipticities on scales ranging from 1' to 30'. We have used data from two different telescopes: ~16.4 deg2 of Canada-France-Hawaii Telescope data and ~7.6 deg2 of Cerro Tololo Inter-American Observatory 4 m data, distributed over 13 widely separated patches. For the first time, a direct comparison can be made of the lensing signal measured using different instruments, which provides an important test of the weak-lensing analysis itself. The measurements obtained from the two telescopes agree well. For the lensing analysis, we use galaxies down to a limiting magnitude of RC=24, for which the redshift distribution is known relatively well. This allows us to constrain some cosmological parameters. For the currently favored ΛCDM model (Ωm=0.3, ΩΛ=0.7, Γ=0.21), we obtain σ8=0.81+0.14-0.19 (95% confidence), in agreement with the 2001 results from Van Waerbeke and coworkers, who used fainter galaxies (and consequently higher redshift galaxies). The good agreement between these two very different weak-lensing studies demonstrates that weak lensing is a useful tool in observational cosmology.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2002
- DOI:
- 10.1086/340298
- arXiv:
- arXiv:astro-ph/0202285
- Bibcode:
- 2002ApJ...572...55H
- Keywords:
-
- Cosmology: Observations;
- Cosmology: Dark Matter;
- Cosmology: Gravitational Lensing;
- Astrophysics
- E-Print:
- accepted for publication in the Astrophysical Journal 11 pages, 12 figures