Weak lensing results from GEMS

Catherine Heymans*, Michael L. Brown, Marco Barden, John A. R. Caldwell, Knud Jahnke, Hans-Walter Rix, Andy N. Taylor, Steve Beckwith, Eric Bell, Andrea Borch, Boris Haeusser, Sharda Jogee, Daniel H. McIntosh, Klaus Meisenheimer, Chen Peng, Sebastian F. Sanchez, Rachel Somerville, Lutz Wisotzki, Christian Wolf

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We present our cosmic shear analysis of the Galaxy Evolution from Morphology and SEDs (GEMS) survey. Imaged with the Advanced Camera for Surveys (ACS) on HST, GEMS provides high resolution imaging spanning some 800 square arcmins in the Chandra Deep Field South (CDFS). We discuss the benefits of using space-based data for weak lensing studies and show that the ACS is a very powerful instrument in this regard. We find that we are not limited by systematic errors arising from the anisotropic ACS point spread function distortion and use our cosmic shear results to place joint constraints on the matter density parameter Q, and the amplitude of the matter power spectrum us, finding sigma(8)(Omega(m)/0.3)(0.62) = 0.73 +/- 0.12. To investigate the impact of atmospheric seeing on weak lensing analysis we compare the shear measured from CDFS galaxies resolved by the COMBO-17 survey and imaged by GEMS. We find good agreement between the two surveys and a higher dispersion in the intrinsic ellipticity distribution of COMBO-17. This dispersion implies that a space-based cosmic shear analysis would yield higher signal-to-noise results compared to a ground-based cosmic shear analysis of the same galaxy sample.

Original languageEnglish
Title of host publicationImpact of Gravitional Lensing on Cosmology
EditorsY Mellier, G Meylan
Place of PublicationNEW YORK
PublisherMac Keith Press, Cambridge Univ Press
Pages43-48
Number of pages6
ISBN (Print)978-0-521-85196-1
DOIs
Publication statusPublished - 2005
Event225th Symposium of the International-Astronomical-Union - Lausanne, Switzerland
Duration: 19 Jul 200423 Jul 2004

Publication series

NameIAU SYMPOSIA
PublisherCAMBRIDGE UNIV PRESS
Volume225
ISSN (Print)0074-1809

Conference

Conference225th Symposium of the International-Astronomical-Union
Country/TerritorySwitzerland
Period19/07/0423/07/04

Keywords

  • COMBO-17 SURVEY
  • EVOLUTION

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