Discovery of a supercluster candidate at $z \sim 1.1$
  We report a promising candidate for a distant supercluster at z $\sim 1.1$ in
the Dark Energy Survey Science Verification data. We examine smoothed semi-3D
galaxy density maps in various photo-z slices. Among several overdense regions,
in this work we report the most significant one as having a $3\sigma$
overdensity at a redshift of $\sim1.1$, over a $\sim160$ Mpc scale, much larger
than the regular cluster scale (several Mpc). The shape of the supercluster is
not circular in the sky projection. Therefore, we regard the point of maximum
overdensity as the center for quantitative measurements. Two different
estimates suggest the mass of the supercluster to be $1.37\substack{+1.31 \\
-0.79} \times 10^{17} M_{\odot}$, more than one order more massive than regular
galaxy clusters. Except for protosuperclusters found with emission-line
galaxies, this could be the most distant supercluster to date defined by
regular galaxies. A spectroscopic confirmation would make this a very
interesting object for cosmology. We discuss the possible implications of such
a massive structure for $\Lambda$CDM cosmology.
