1505.02307
Chromatic CCD effects on weak lensing measurements for LSST
Meyers, Burchat
Wavelength-dependent PSFs violate an implicit assumption in current galaxy shape measurement algorithms that deconvolve the PSF measured from stars (which have stellar SEDs) from images of galaxies (which have galactic SEDs). Since the absorption length of Si depends on wavelength, CCDs are a potential source of PSF chromaticity. Develop two toy models to estimate the sensitivity of the cosmic shear survey from the LSST to chromatic effects in CCDs. Then compare these toy models to simulated estimates of PSF chromaticity derived from the LSST photon simulator PhoSim. Find that even though sensor contributions to PSF chromaticity are subdominant to atmospheric contributions, they can still significantly bias cosmic shear results if left uncorrected, particularly in the redder filter bands and for objects that are off-axis in the field of view.
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