Between the years of 1997 to 2012, astronomers mapped these bursts in the sky, with the help of the robotic satellites Swift and Fermi which looks for gamma-ray bursts and measures their redshifts. In the map they produced, they noticed something interesting; 14 gamma-ray bursts have very similar redshifts and are very close to each other. This means that there is a very large group of galaxies and matter in the region. They say, from measuring these bursts, comes up with a very large structure measuring 10 billion light-years in diameter.