SDSSJ2222+2745 A Gravitationally Lensed Sextuple Quasar with Maximum
  Image Separation of 15.1" Discovered in the Sloan Giant Arcs Survey
  We report the discovery of a unique gravitational lens system,
SDSSJ2222+2745, producing five spectroscopically confirmed images of a z_s=2.82
quasar lensed by a foreground galaxy cluster at z_l=0.49. We also present
photometric and spectroscopic evidence for a sixth lensed image of the same
quasar. The maximum separation between the quasar images is 15.1". Both the
large image separations and the high image multiplicity of the lensed quasar
are in themselves exceptionally rare, and observing the combination of these
two factors is an exceptionally unlikely occurrence in present datasets. This
is only the third known case of a quasar lensed by a cluster, and the only one
with six images. The lens system was discovered in the course of the Sloan
Giant Arcs Survey, in which we identify candidate lenses in the Sloan Digital
Sky Survey and target these for follow up and verification with the 2.56m
Nordic Optical Telescope. Multi-band photometry obtained over multiple epochs
from September 2011 to September 2012 reveal significant variability at the
~10-30% level in some of the quasar images, indicating that measurements of the
relative time delay between quasar images will be feasible. In this lens system
we also identify a bright (g = 21.5) giant arc corresponding to a strongly
lensed background galaxy at z_s=2.30. We fit parametric models of the lens
system, constrained by the redshift and positions of the quasar images and the
redshift and position of the giant arc. The predicted time delays between
different pairs of quasar images range from ~100 days to ~6 years.
