ESO Science Release | 2015 Dec 15
Observations from ESO telescopes provide crucial third dimension in probe of Universe’s dark side
[c][imghover=http://cdn.eso.org/images/screen/eso1548c.jpg]http://cdn.eso.org/images/screen/eso1548b.jpg[/imghover]Distant Galaxy Cluster Discovered in the XXL SurveyESO telescopes have provided an international team of astronomers with the gift of the third dimension in a plus-sized hunt for the largest gravitationally bound structures in the Universe — galaxy clusters. Observations by the VLT and the NTT complement those from other observatories across the globe and in space as part of the XXL survey — one of the largest ever such quests for clusters.
Credit: ESA/XXL consortium/Canada France Hawaii Telescope[/c][hr][/hr]
Galaxy clusters are massive congregations of galaxies that host huge reservoirs of hot gas — the temperatures are so high that X-rays are produced. These structures are useful to astronomers because their construction is believed to be influenced by the Universe’s notoriously strange components — dark matter and dark energy. By studying their properties at different stages in the history of the Universe, galaxy clusters can shed light on the Universe’s poorly understood dark side.
The team, consisting of over 100 astronomers from around the world, started a hunt for the cosmic monsters in 2011. Although the high-energy X-ray radiation that reveals their location is absorbed by the Earth’s atmosphere, it can be detected by X-ray observatories in space. Thus, they combined an ESA XMM-Newton survey — the largest time allocation ever granted for this orbiting telescope — with observations from ESO and other observatories. The result is a huge and growing collection of data across the electromagnetic spectrum, collectively called the XXL survey. ...
XXL Survey Papers, Astronomy & Astrophysics, arXiv.org