Magnification as a Tool in Weak Lensing
  Weak lensing surveys exploit measurements of galaxy ellipticities. These
measurements are subject to errors which degrade the cosmological information
that can be extracted from the surveys. Here we propose a way of using the
galaxy data themselves to calibrate the measurement errors. In particular, the
cosmic shear field, which causes the galaxies to appear elliptical, also
changes their sizes and fluxes. Information about the sizes and fluxes of the
galaxies can be added to the shape information to obtain more robust
information about the cosmic shear field. The net result will be tighter
constraints on cosmological parameters such as those which describe dark
energy.
