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Session 13 - Large Scale Structure & Cosmology.
Display session, Monday, January 13
The results of spectroscopic observations of 42 R \ge 1 clusters of galaxies from the Abell (1958) and Abell, Corwin, amp; Olowin (1989 - hereafter ACO) catalogs are presented. The observations were conducted at the ESO 3.6m telescope with the MEFOS multiple-fiber spectrograph. Thirty-seven of the clusters lie in a 10^\circ \times 50^\circ strip of sky that contains two supercluster candidates (in Aquarius and Eridanus) that were identified by a percolation analysis of the Abell and ACO catalogs. This strip is now complete in redshift measurements to the point that all R \ge 1 clusters with m_10 < 18.3 (on the ACO scale) have at least one measured redshift per cluster. Most clusters have at least 5 measured redshifts. Seven other clusters were observed in a supercluster candidate in the Grus-Indus region.
We find that one of the supercluster candidates is a filament of 22 clusters in a 13\times overdensity that extends at least 210 h^-1 Mpc. This filament runs predominantly along the line of sight in the Aquarius region from z=0.08 to z=0.16. The extent of this supercluster is comparable to the largest structures previously found in the local universe (e. g., the Great Wall and Perseus-Pegasus). The Aquarius supercluster also contains a `knot' of six clusters at redshift z \sim 0.11 that represents an overdensity of 200 times the average spatial number density for ACO clusters. Two other similar cluster density enhancements have been identified within z \le 0.11: Corona Borealis and the Shapley Concentration.
Program listing for Monday