Cosmic Shear with Keck: Systematic Effects
Cosmic shear probes the distribution of dark matter via gravitational lensing of distant, background galaxies. We describe our cosmic shear survey consisting of deep blank fields observed with the Keck II telescope. We have found biases in the standard weak lensing analysis, which are enhanced by the elongated geometry of the Keck fields. We show how these biases can be diagnosed and corrected by masking edges and chip defects.