PICS: Simulations of Strong Gravitational Lensing in Galaxy Clusters
  Gravitational lensing has become one of the most powerful tools available for
investigating the 'dark side' of the universe. Cosmological strong
gravitational lensing, in particular, probes the properties of the dense cores
of dark matter halos over decades in mass and offers the opportunity to study
the distant universe at flux levels and spatial resolutions otherwise
unavailable. Studies of strongly-lensed variable sources offer yet further
scientific opportunities. One of the challenges in realizing the potential of
strong lensing is to understand the statistical context of both the individual
systems that receive extensive follow-up study, as well as that of the larger
samples of strong lenses that are now emerging from survey efforts. Motivated
by these challenges, we have developed an image-simulation pipeline, PICS
(Pipeline for Images of Cosmological Strong lensing) to generate realistic
strong gravitational lensing signals from group and cluster scale lenses. PICS
uses a low-noise and unbiased density estimator based on (resampled) Delaunay
Tessellations to calculate the density field; lensed images are produced by
ray-tracing images of actual galaxies from deep Hubble Space Telescope
observations. Other galaxies, similarly sampled, are added to fill in the light
cone. The pipeline further adds cluster-member galaxies and foreground stars
into the lensed images. The entire image ensemble is then observed using a
realistic point spread function which includes appropriate detector artifacts
for bright stars. Noise is further added, including such non-Gaussian elements
as noise window-paning from mosaiced observations, residual bad pixels, and
cosmic rays. The aim is to produced simulated images that appear identical - to
the eye (expert or otherwise) - to real observations in various imaging
surveys.
