Localizing Transformations of the Galaxy-Galaxy Lensing Observable
  Modern cosmological analyses of galaxy-galaxy lensing face a theoretical
systematic effect arising from the non-locality of the observed galaxy-galaxy
lensing signal. Because the predicted tangential shear signal at a given
separation depends on the physical modeling on all scales internal to that
separation, systematic uncertainties in the modeling of non-linear small scales
are propagated outwards to larger scales. Even in the absence of other limiting
factors, this systematic effect alone can necessitate conservative small-scale
cuts, resulting in significant losses of information in the tangential shear
data vector. We construct a simple linear transformation of the observable that
removes this non-locality, enabling more aggressive small-scale cuts for a
given theoretical model. Our modified galaxy-galaxy lensing observable makes it
possible to include observations on significantly smaller scales than those
under the standard approach in cosmological analyses. More importantly, it
ensures that the cosmological signal contained within the observable is
exclusively drawn from well-understood physical scales.
