Discovery of Extreme Examples of Superclustering in Aquarius

We report the discovery of two highly extended filaments and one extremelyhigh density knot within the region of Aquarius. The supercluster candidateswere chosen via percolation analysis of the Abell and ACO catalogs and includeonly the richest clusters (R >= 1). The region examined is a 10x45 degree stripand is now 87% complete in cluster redshift measurements to mag_10 = 18.3. Inall, we report 737 galaxy redshifts in 46 cluster fields. One of thesuperclusters, dubbed Aquarius, is comprised of 14 Abell/ACO clusters andextends 110h^-1Mpc in length only 7 degrees off the line-of-sight. On thenear-end of the Aquarius filament, another supercluster, dubbed Aquarius-Cetus,extends for 75h^-1Mpc perpendicular to the line-of-sight. After fittingellipsoids to both Aquarius and Aquarius-Cetus, we find axis ratios (long-to-midlength axis) of 4.3 for Aquarius and 3.0 for Aquarius-Cetus. We fitellipsoids to all N>=5 clumps of clusters in the Abell/ACO measured-z clustersample. The frequency of filaments with axis ratios >=3.0 (~20%) is nearlyidentical with that found among `superclusters' in Monte Carlo simulations ofrandom and random- clumped clusters, however, so the rich Abell/ACO clustershave no particular tendency toward filamentation. The Aquarius filament alsocontains a `knot' of 6 clusters at Z ~0.11, with five of the clusters nearenough togeteher to represent an apparent overdensity of 150. There arethree other R >= 1 cluster density enhancements similar to this knot at lowerredshifts: Corona Borealis, the Shapely Concentration, and another grouping ofseven clusters in Microscopium. All four of these dense superclusters appearnear the point of breaking away from the Hubble Flow, and some may now be incollapse, but there is little evidence of any being virialized.Comment: 45 pages (+ e-tables), 7 figures, AASTeX Accepted for Publication in Ap