出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：In these proceedings we present a cosmic shear analysis of data from the HST/ACS Parallel
Cosmic Shear Survey. Due to its relatively large eld-of-view in combination with space-based
resolution, ACS provides excellent conditions to measure cosmic shear on small and intermediate
angular scales. We used 54 deep ACS/WFC images with an average galaxy number density of
85 per square arcminute for the cosmic shear analysis. We thoroughly investigated the effect
of the HST/ACS point spread function (psf) on the shear measurement. To account for the low
number of stars present in many elds at high galactic latitudes, we developed a new method for
the psf anisotropy correction using a superposition of template patterns. Our preliminary cosmic
shear results are consistent with LCDM predictions with s8 = 0:8. We still nd indications for a
remaining contamination of our data with systematic effects. Once these remaining systematics
are properly understood and corrected, it will be possible to measure cosmic shear at small scales
with the ACS Parallel Cosmic Shear Survey with unprecedented precision.
