Weak Lensing Measurements in Simulations of Radio Images
  We present a study of weak lensing shear measurements for simulated galaxy
images at radio wavelengths. We construct a simulation pipeline into which we
can input galaxy images of known ellipticity, and with which we then simulate
observations with eMERLIN and the international LOFAR array. The simulations
include the effects of the CLEAN algorithm, uv sampling, observing angle, and
visibility noise, and produce realistic restored images of the galaxies. We
apply a shapelet-based shear measurement method to these images and test our
ability to recover the true source ellipticities. We model and deconvolve the
effective PSF, and find suitable parameters for CLEAN and shapelet
decomposition of galaxies. We demonstrate that ellipticities can be measured
faithfully in these radio simulations, with no evidence of an additive bias and
a modest (10%) multiplicative bias on the ellipticity measurements. Our
simulation pipeline can be used to test shear measurement procedures and
systematics for the next generation of radio telescopes.
