Chromatic CCD effects on weak lensing measurements for LSST
  Wavelength-dependent point spread functions (PSFs) violate an implicit
assumption in current galaxy shape measurement algorithms that deconvolve the
PSF measured from stars (which have stellar spectral energy distributions
(SEDs)) from images of galaxies (which have galactic SEDs). Since the
absorption length of silicon depends on wavelength, CCDs are a potential source
of PSF chromaticity. Here we develop two toy models to estimate the sensitivity
of the cosmic shear survey from the Large Synoptic Survey Telescope to
chromatic effects in CCDs. We then compare these toy models to simulated
estimates of PSF chromaticity derived from the LSST photon simulator PhoSim. We
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.
