Cosmic Shear Systematics: Software-Hardware Balance

Understand

Cosmic shear measurements rely on our ability to measure and correct the Point Spread Function (PSF) of the observations.

• This PSF is measured using stars in the field, which give a noisy measure at random points in the field.
• Using Wiener filtering, we show how errors in this PSF correction process propagate into shear power spectrum errors.
• This allows us to test future space-based missions, such as Euclid or JDEM, thereby allowing us to set clear engineering specifications on PSF variability.