RadioLensfit: Bayesian weak lensing measurement in the visibility domain
  Observationally, weak lensing has been served so far by optical surveys due
to the much larger number densities of background galaxies achieved, which is
typically by two to three orders of magnitude compared to radio. However, the
high sensitivity of the new generation of radio telescopes such as the Square
Kilometre Array (SKA) will provide a density of detected galaxies that is
comparable to that found at optical wavelengths, and with significant source
shape measurements to make large area radio surveys competitive for weak
lensing studies. This will lead weak lensing to become one of the primary
science drivers in radio surveys too, with the advantage that they will access
the largest scales in the Universe going beyond optical surveys, like LSST and
Euclid, in terms of redshifts that are probed. RadioLensfit is an adaptation to
radio data of "lensfit", a model-fitting approach for galaxy shear measurement,
originally developed for optical weak lensing surveys. Its key advantage is
working directly in the visibility domain, which is the natural approach to
adopt with radio data, avoiding systematics due to the imaging process. We
present results on galaxy shear measurements, including investigation of
sensitivity to instrumental parameters such as the visibilities gridding size,
based on simulations of individual galaxy visibilities performed by using
SKA1-MID baseline configuration. We get an amplitude of the shear bias in the
method comparable with SKA1 requirements for a population of galaxies with
realistic flux and scalelength distributions estimated from the VLA SWIRE
catalog.
