EDP Sciences
Free access
Issue
A&A
Volume 395, Number 2, November IV 2002
Page(s) 385 - 397
Section Cosmology
DOI http://dx.doi.org/10.1051/0004-6361:20021137


A&A 395, 385-397 (2002)
DOI: 10.1051/0004-6361:20021137

Wide field weak lensing observations of A1835 and A2204

D. Clowe1, 2 and P. Schneider1, 2

1  Institut für Astrophysik und Extraterrestrische Forschung der Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
2  Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching, Germany

(Received 19 April 2002 / Accepted 5 August 2002 )

Abstract
We present mass reconstructions from weak lensing for the galaxy clusters A1835 and A2204 over $34\arcmin \times 34\arcmin$ fields using data from the ESO/MPG Wide Field Imager. Using a background galaxy population of 22<R<25.5 we detect the gravitational shear of A1835 at $8.8\sigma$ significance, and obtain best-fit mass profiles of $\sigma_v=1233^{+66}_{-70}$ km s -1 for a singular isothermal sphere model and r200=1550 h -1 kpc, c=2.96 for a "universal" CDM profile. Using a color-selected background galaxy population of 22<R<25.8 we detect the gravitational shear of A2204 at $7.2\sigma$ significance, and obtain best-fit mass profiles of $\sigma_v=1035^{+65}_{-71}$ km s -1 for a SIS model and r200=1310 h-1 km s -1, c=6.3 for a "universal" CDM profile. The gravitational shear at distances greater than $10\arcmin $ is significantly detected for both clusters. The best fit weak lensing cluster masses agree well with both X-ray and dynamical mass measurements, although the central concentration of A1835 is much lower in the weak lensing mass profile than that measured by recent Chandra results. We suggest that this lower concentration is most likely a combination of contamination of the "background" galaxy population with cluster dwarf galaxies and the effect of a prolate or tri-axial cluster core with the major axis lying near the plane of the sky. We also detect a number of additional structures at moderate significance, some of which appear to be sub-haloes associated with the clusters.


Key words: gravitational lensing -- galaxies: clusters: individual: A1835 -- galaxies: clusters: individual: A2204 -- dark matter

Offprint request: D. Clowe, clowe@astro.uni-bonn.de

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