A NEARBY MASSIVE GALAXY CLUSTER BEHIND THE MILKY-WAY

THE recession velocities of relatively nearby galaxies show systematic deviations from a uniform expansion field, These deviations indicate the presence of the 'Great Attractor'-a large concentration of mass (s imilar to 5 x 10(16) solar masses) that lies in the direction of the s outhern Milky Way(1,2), Attempts to quantify both the nature and exten t of the Great Attractor(3-11) have been hampered by the fact that it is largely hidden by the disk of the Milky Way. Although there is an e xcess of galaxies in this region(12), no dominant galaxy cluster or ot her concentration of mass has hitherto been identified, Here we presen t results from a survey of galaxies obscured (or partially obscured) b y the southern Milky Way, Our results show that a previously identifie d galaxy cluster, Abell 3627, which lies only 9 degrees from the predi cted centre of the Great Attractor(13), is very massive (similar to 5 x 10(15) solar masses). The cluster's redshift is also near that predi cted for the core of the Great Attractor(2,3,12-14), suggesting that i t lies at or near the bottom of the Attractor's gravitational potentia l well.