Chandra Spots a Mega-Cluster of Galaxies in the Making | Space
Astronomers using data from NASA’s Chandra X-ray Observatory & other telescopes have put together a comprehensive map of a rare encounter between four galaxy clusters. Eventually, all four groups — each with a mass of at least many hundred trillion times that of the Sun — will join to form one of the gigantic objects in the universe.
Galaxy clusters are the most massive structures in the cosmos that are held together by gravity. Groups consist of hundreds or even thousands of galaxies embedded in the hot gas, and contain an even more considerable amount of invisible dark matter. Sometimes two galaxy clusters collide, as in the case of the Bullet Cluster, and occasionally more than two will clash at the same time.
The new researches show a mega-structure being assembled in a system called Abell 1758, located about 3 Bn light-years from Earth. It includes two pairs of colliding galaxy clusters that are traveling toward one another. Scientists first identified Abell 1758 as a quadruple galaxy cluster system in 2004 using data from Chandra and XMM-Newton, a satellite commanded by the European Space Agency (ESA).
Each pair in the system holds two galaxy clusters that are well on their way to joining. In the northern (top) pair seen in the composite image, the centers of each group have already passed by each other once, about 300 to 400 million years ago, and will eventually swing back around. The southern pair at the bottom of the image has two clusters that are close to approaching each other for the 1st time.
Image Credit: X-ray: NASA/CXC/SAO/G.Schellenberger et al.; Optical:SDSS