EDP Sciences
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Volume 432, Number 3, March IV 2005
Page(s) 797 - 808
Section Cosmology (including clusters of galaxies)
DOI http://dx.doi.org/10.1051/0004-6361:20034573

A&A 432, 797-808 (2005)
DOI: 10.1051/0004-6361:20034573

Cosmic Shear from STIS pure parallels

III. Analysis of Cycle 9 pure parallels
J.-M. Miralles1, T. Erben1, H. Hämmerle1, 2, P. Schneider1, W. Freudling3, N. Pirzkal3 and R. A. E. Fosbury3

1  Institut für Astrophysik und Extraterrestrische Forschung der Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
    e-mail: miralles@astro.uni-bonn.de
2  Max-Planck Institut für Astrophysik, Karl-Schwarzschild Str. 1, 85748 Garching bei München, Germany
3  ST-ECF, Karl-Schwarzschild Str. 2, 85748 Garching bei München, Germany

(Received 24 October 2003 / Accepted 10 November 2004 )

Following the detection of a cosmic shear signal at the 30'' scale using archival parallel data from the STIS CCD camera onboard HST in the previous paper of this series, we analyzed a larger data set obtained from an HST GO pure parallel program. Although this data set is considerably larger than the one analyzed previously, we do not obtain a significant detection of the cosmic shear signal. The most likely cause of this null result is that the signal is comparable to (or less than) the random measurement of the noise. We also show that multiple systematics plague the STIS CCD data for its use in cosmic shear programs, and in particular the continuous degradation of the CCD charge transfer efficiency after 4 years in space, which is a source of additional noise that is still difficult to correct for in the absence of physical models.

Key words: cosmology: theory -- dark matter -- gravitational lensing -- large-scale structure of Universe

© ESO 2005