On the origin of the dipole anisotropy of the cosmic microwave background: beyond the Hydra-Centaurus supercluster.

The authors discuss the properties of a large concentration of galaxies located in the direction of the Centaurus cluster but at a much larger distance. They find that the majority of the faint galaxies in the region are clustered around cz ≡ 14000 km/sec and define a rich supercluster having a dynamical mass close to 2.5×10¹⁵M_sun;. The authors show that this mass is not sufficient to explain the peculiar velocity of ≡600 km/sec of the Local Group with respect to the cosmic microwave background in the general direction of Centaurus. They find no luminous galaxies in the redshift range 6000 - 8000 km/sec in that direction. This implies that any mass overdensity related to the anisotropy of the Hubble flow must be either dark, hidden by the galactic plane or considerably more distant than 14000 km/sec.