Free Astronomy Magazine November-December 2018

35 NOVEMBER-DECEMBER 2018 SPACE CHRONICLES billion years after the Big Bang,” explained the first author of the discovery paper, Olga Cucciati. “Normally these kinds of structures are known at lower redshifts, which means when the Universe has had much more time to evolve and con- struct such huge things. It was a surprise to see something this evol- ved when the Universe was rela- tively young!” Located in the COSMOS field in the constellation of Sextans (The Sex- tant), Hyperion was identified by analysing the vast amount of data obtained from the VIMOS Ultra- deep Survey led by Olivier Le Fèvre (Aix-Marseille Université, CNRS, CNES). The VIMOS Ultra-Deep Sur- vey provides an unprecedented 3D map of the distribution of over 10000 galaxies in the distant Uni- verse. The team found that Hyperion has a very complex structure, contain- ing at least 7 high-density regions connected by filaments of galaxies, and its size is comparable to nearby superclusters, though it has a very different structure. “Superclusters closer to Earth tend to a much more concentrated distribution of mass with clear structural features,” explains Brian Lemaux, an astronomer from Uni- versity of California, Davis and LAM, and a co-leader of the team behind this result. “But in Hyper- ion, the mass is distributed much more uniformly in a series of con- nected blobs, populated by loose associations of galaxies.” This contrast is most likely due to the fact that nearby superclusters have had billions of years for grav- ity to gather matter together into denser regions — a process that has been acting for far less time in the much younger Hyperion. Given its size so early in the history of the Universe, Hyperion is ex- pected to evolve into something similar to the immense structures in the local Universe such as the super- clusters making up the Sloan Great Wall or the Virgo Supercluster that contains our own galaxy, the Milky Way. “Understanding Hyperion and how it compares to similar recent structures can give insights into how the Universe developed in the past and will evolve into the future, and allows us the opportunity to challenge some models of super- cluster formation,” concluded Cuc- ciati. “Unearthing this cosmic titan helps uncover the history of these large-scale structures .” !