The Shapley Supercluster. II. Spectroscopic observations in a wide area and general morphology

We report 2868 new multiobject spectroscopic measurements of galaxy redshifts in an area roughly 12 degrees x 6 degrees (right ascension x declination) centered on the Shapley Supercluster (SSC). These correspond to 2627 different galaxies. Including other measurements reported in the literature, the total number of galaxies with measured redshifts in a 19 degrees x 16 degrees area centered on the supercluster now reaches 5090. Of these, 949 lie in the redshift range 9000-18,000 km s(-1), which we tentatively identify with the SSC. This unprecedented sample allows a quite detailed qualitative morphological study of the SSC. Based on the three-dimensional distribution of galaxies and clusters of galaxies, we identify several subcondensations of the supercluster, as well as walls and filaments connecting them. We also iind another supercluster in the background, at redshift similar to 23,000 km s(-1).