A supercluster of IRAS galaxies behind the Great Attractor

The dynamics of nearby galaxies support the existence of a large concentration of mass (the 'Great Attractor') in the Centaurus region at a redshift (z) between 0.012 and 0.015 have suggested a concentration of rich clusters of galaxies at z∼0.05 in the Centaurus region may also have a significant role in perturbing the local Hubble flow. The existence of such overdense regions in the Universe would have a profound effect on ideas about the formation of large-scale structure. At present the reality of such regions is supported by some, but not by all, studies of the streaming of distant galaxies. We demonstrate here that redshifts of galaxies that are in the Infrared Astronomical Satellite (IRAS) survey show the existence of an extended supercluster at z∼0.05 surrounding the concentration of clusters. Its contribution to the Local Group peculiar (non-Hubble) velocity is probably minor, although it may dominate motions on the far side of the Great Attractor. (author)