  Research over the past three decades has revolutionized the field of
cosmology while supporting the standard cosmological model. However, the
cosmological principle of Universal homogeneity and isotropy has always been in
question, since structures as large as the survey size have always been found
as the survey size has increased. Until now, the largest known structure in our
Universe is the Sloan Great Wall (SGW), which is more than 400 Mpc long and
located approximately one billion light-years away. Here we report the
discovery of a structure at least six times larger than the Sloan Great Wall
that is suggested by the distribution of gamma-ray bursts (GRBs). Gamma-ray
bursts are the most energetic explosions in the Universe. They are associated
with the stellar endpoints of massive stars and are found in and near distant
galaxies. Therefore, they are very good indicators of the dense part of the
Universe containing normal matter. As of July 2012, 283 GRB redshifts have been
measured. If one subdivides this GRB sample into nine radial parts and compares
the sky distributions of these subsamples (each containing 31 GRBs), one can
observe that the fourth subsample (1.6 < z < 2.1) differs significantly from
the others in that many of the GRBs are concentrated in the same angular area
of the sky. Using the two-dimensional Kolmogorov-Smirnov test, the significance
of this observation is found to be less than 0.05 per cent. Fourteen out of the
31 Gamma-Ray Bursts in this redshift band are concentrated in approximately 1/8
of the sky. The binomial probability to find such a deviation is p=0.0000055.
This huge structure lies ten times farther away than the Sloan Great Wall, at a
distance of approximately ten billion light-years. The size of the structure
defined by these GRBs is about 2000-3000 Mpc, or more than six times the size
of the largest known object (SGW) in the Universe.
