A study of the core of the Shapley Concentration – I. The sample

• Published in: Monthly notices of the Royal Astronomical Society 1994-04, Vol.267 (3), p.665-691
• Main Authors: Bardelli, Sandro, Zucca, Elena, Vettolani, Giampaolo, Zamorani, Giovanni, Scaramella, Roberto, Collins, Chris A., MacGillivray, Harvey T.
• Format: Article
• Language: English
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; galaxies: clusters: individual: Shapley Concentration; galaxies: distances and redshifts; Galaxy groups, clusters, and superclusters. Large-scale structure of the universe; large-scale structure of Universe; Stellar systems. Galactic and extragalactic objects and systems. The universe; Superclusters. Large-scale structure of the universe (including voids, pancakes, great wall, etc.)
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/267.3.665

We report the first results of a spectroscopic survey of galaxies in the core of the Shapley Concentration, the richest nearby supercluster of clusters of galaxies. We have measured 311 new galaxy redshifts in an area of ∼ 4.5 deg2 centred on the Abell cluster A3558. When the data already available in the literature are also considered, the total number of galaxy redshifts in this area amounts to more than 500. On the basis of these data, we estimate the mean velocities and the velocity dispersions of the Abell clusters A3556 and A3558 and the poor cluster SC 1329 – 314. Finally, from an analysis of the projected and three-dimensional distributions of galaxies in this region, we estimate the galaxy overdensity and find that the core of the Shapley Concentration is in an interesting, very complex dynamical state: the main clusters appear to be interacting with each other, forming a single elongated structure containing many subcondensations.