Astronomical instrumentation

Abstract:

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 (refs 1, 2). Scaramella et al3 have suggested that 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 structure4. At present the reality of such regions is supported by some, but not by all, studies of the streaming of distant galaxies1,2,5-9. 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 described by Scaramella et al. 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. © 1990 Nature Publishing Group.