Hubble Space Telescope Combined Strong and Weak Lensing Analysis of the
  CLASH Sample: Mass and Magnification Models and Systematic Uncertainties
  We present results from a comprehensive lensing analysis in HST data, of the
complete CLASH cluster sample. We identify new multiple-images previously
undiscovered allowing improved or first constraints on the cluster inner mass
distributions and profiles. We combine these strong-lensing constraints with
weak-lensing shape measurements within the HST FOV to jointly constrain the
mass distributions. The analysis is performed in two different common
parameterizations (one adopts light-traces-mass for both galaxies and dark
matter while the other adopts an analytical, elliptical NFW form for the dark
matter), to provide a better assessment of the underlying systematics - which
is most important for deep, cluster-lensing surveys, especially when studying
magnified high-redshift objects. We find that the typical (median), relative
systematic differences throughout the central FOV are $\sim40\%$ in the
(dimensionless) mass density, $\kappa$, and $\sim20\%$ in the magnification,
$\mu$. We show maps of these differences for each cluster, as well as the mass
distributions, critical curves, and 2D integrated mass profiles. For the
Einstein radii ($z_{s}=2$) we find that all typically agree within $10\%$
between the two models, and Einstein masses agree, typically, within
$\sim15\%$. At larger radii, the total projected, 2D integrated mass profiles
of the two models, within $r\sim2\arcmin$, differ by $\sim30\%$. Stacking the
surface-density profiles of the sample from the two methods together, we obtain
an average slope of $d\log (\Sigma)/d\log(r)\sim-0.64\pm0.1$, in the radial
range [5,350] kpc. Lastly, we also characterize the behavior of the average
magnification, surface density, and shear differences between the two models,
as a function of both the radius from the center, and the best-fit values of
these quantities.
