Shapley Supercluster
The Shapley Supercluster ( SCl 124) represents the largest collection of star systems at a distance of up to 700 million light years dar. He is a center of mass, which ensures that its member star systems are held together by gravitational forces, so no in its sphere of influence increase in the distances between galaxies can be observed due to the general expansion of the universe.
The Shapley Supercluster appears as a significant concentration of star systems in the constellation Centaurus. Its distance from the Milky Way is about 650 million light years ( redshift z = 0.046 ).
The structure of the Shapley supercluster was discovered by Somak Raychaudhury at a screening of the sky ( again ). Raychaudhury examined photographic plates with images of the southern sky with an automated screening system (APM ) at the University of Cambridge. In his treatise, he named the structure after the astronomer Harlow Shapley found that had these galaxies accumulation found in an earlier survey of the sky first. Around the same time, astronomers had identified to Roberto Scaramella this concentration of star systems as a remarkable structure in the cosmos and they called alpha concentration.
Discovery history
In the late 1920s, Harlow Shapley began with colleagues at the Observatory of Harvard University, a search for galaxies in the southern sky, where they were evaluating photographic plates that had been taken with the 24-inch Bruce telescope in Bloemfontein, South Africa. 1932 reported Shapley based on the evaluation, the identification of at least 76,000 galaxies brighter than 18 likes in one-third of the southern sky. Some of this data is later published as part of the Harvard galaxy counts were performed to determine the density and distribution of binary systems in space.
In the catalog Shapley recorded most systems of " Coma- Virgo cloud" ( which is now defined as an overlay zone of the Virgo supercluster and the Coma supercluster ), and he found in the constellation Centaurus another " cloud", which he described as overwhelming concentration of galaxies described. This concentration impressed him because of its vast scale, the number of star systems and the elongated shape. This characterization is consistent with the known today as the core region of the Shapley supercluster region of the cosmos. Shapley estimated the distance to the structure to 14 times the distance to the Virgo Supercluster, where he was based on the average apparent diameter of the observed stellar systems. Starting from the current distance estimate for the Virgo Supercluster results in the removal of 231 Megaparsek.
Current research
The Shapley supercluster extends in the direction of the presumed motion vector on which the Local Group, which also includes our Milky Way belongs, moves through the cosmos. This suggests that the Shapley Supercluster could be a major cause of the motion of the Local Group, while only the structure of the Great Attractor was taken as a possible center of mass responsible before. This new estimate has triggered an intense observation of the Shapley supercluster.