THE ASTRONOMICAL JOURNAL    VOLUME 110, NUMBER 2, PAGE 463          AUGUST 1995

            THE SHAPLEY SUPERCLUSTER. I. SPECTROSCOPIC OBSERVATIONS
                             IN THE CENTRAL REGION

                          H. QUINTANA AND A. RAMIREZ

    Grupo de Astrofisica, P. Universidad Catolica de Chile, Santiago, Chile
                    Electronic mail: hquintan@astro.puc.cl

                                 JORGE MELNICK

                European Southern Observatory, La Silla, Chile
                       Electronic mail: jmelnick@eso.org

                              SOMAK RAYCHAUDHURY

     Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts

                                  ERIC SLEZAK

     Observatoire de la Cote d'Azur, BP 229, F06304, Nice Cedex 4, France
                  Electronic mail: slezak@rameau.obs-nice.fr


                                   ABSTRACT

    We present a new analysis of the kinematics of the Shapley supercluster
    based on radial velocities for 1087 galaxies in the clusters A3558
    (Shapley 8), A3528 (Klemola 21), A3532 (Klemola 22), A3530, A3556 (SC
    1321-314), A3559 (CE 1327-292), A3560, A3562, SC 1329-314 and in the
    intercluster region of the core of the supercluster, of which 367 are
    new measurements.  We also present accurate positions from APM and MAMA
    scans of the ESO/SERC Southern Sky Survey photographic plates.  We
    obtain new velocity dispersions and estimate the masses of the member
    clusters, evaluating dynamical models of the supercluster.  The
    supercluster is found to be significantly flattened.  We find that for
    Omega_0=0.3, H_0=75 km/s/Mpc, the gravitational pull of the
    supercluster may account for up to 25% of the peculiar velocity of the
    Local Group required to explain the dipole anisotropy of the Cosmic
    Microwave Background radiation, in which case the mass of the
    supercluster would be dominated by intercluster dark matter.  This
    fractional contribution would be considerably higher for combinations
    of significantly lower values of Omega_0 and higher values of H_0.