AStroLens: Automatic Strong-Lens Modeling of X-ray Selected Galaxy
  Clusters
  We use AStroLens, a newly developed gravitational lens-modeling code that
relies only on geometric and photometric information of cluster galaxies as
input, to map the strong-lensing regions and estimate the lensing strength of
96 galaxy clusters at $z=0.5$-$0.9$. All clusters were identified during the
extended Massive Cluster Survey (eMACS) based on their X-ray flux and optical
appearance. Building on the well tested assumption that the distribution of
both luminous and dark matter in galaxy clusters is approximately traced by the
distribution of light, i.e., that light traces mass, AStroLens uses three
global parameters to automatically model the deflection from
strong-gravitational lensing for all galaxy clusters in this diverse sample. We
test the robustness of our code by comparing AStroLens estimates derived solely
from shallow optical images in two passbands with the results of in-depth
lens-modeling efforts for two well studied eMACS clusters and find good
agreement, both with respect to the size and the shape of the strong-lensing
regime delineated by the respective critical lines. Our study finds 31 eMACS
clusters with effective Einstein radii ($\theta_{E}$) in excess of 20" and
eight with $\theta_{E} >$ 30", thereby underlining the value of X-ray selection
for the discovery of powerful cluster lenses that complement giants like
MACSJ0717 at ever-increasing redshift. As a first installment toward the public
release of the eMACS sample, we list physical properties of the ten calibration
clusters as well as of the ten most powerful eMACS cluster lenses, according to
AStroLens.
