At the centre of the local supercluster
there is a gravitational anomaly, known as the Great Attractor
, which is drawing in galaxies over a region hundreds of millions of light years across.
These galaxies are all redshifted
, in accordance with the 'Hubble flow', as if they were receding from us and from each other, but the variations in their redshift are sufficient to reveal the existence of a concentration of mass equivalent to tens of thousands of galaxies.
The Great Attractor, discovered in 1986, lies at a distance of between 150 million and 250 million light years (250 million is the most recent estimate), in the direction of the Hydra and Centaurus constellations. In its vicinity there is a preponderance of large old galaxies, many of which are colliding with their neighbours, and/or radiating large amounts of radio waves.