AAS Meeting #193 - Austin, Texas, January 1999
Session 39. Cosmology/Large Scale Structure
Display, Thursday, January 7, 1999, 9:20am-6:30pm, Exhibits Hall 1

## [39.10] Discovery of Two Highly Extended, Filamentary Superclusters in Aquarius

D. Batuski, C. Miller, K. Slinglend (U. Maine), C. Balkowski, S. Maurogordato, V. Cayatte, P. Felenbok (Obs. de Paris, Meudon), R. Olowin (St. Mary's College, CA)

We conducted percolation analyses of a sample of all R \ge 1 Abell/ACO clusters with measured redshifts, including results from two of our own recent redshift surveys, which provided 200 cluster redshifts based on multiple-galaxy observations. With a percolation parameter b = 25 h-1 Mpc (spatial number density n = 8\bar{n}), the Aquarius supercluster of Miller et al. 1998 (BAAS, 28, 1289) appears as a collection of 14 R \ge 1 clusters with a maximum extent of ~110 h-1 Mpc, the longest such supercluster identified to date. This filament of clusters runs within 7\circ of the line of sight.

Our analysis also reveals that another supercluster, Aquarius-Cetus, consisting of eight rich clusters with an extent of ~75 h-1 Mpc, runs roughly perpendicular to Aquarius near its low-redshift end.

Both of these superclusters are remarkably filamentary. Fitting ellipsoids to all N \ge 5 clumps of clusters (at b = 25 h-1 Mpc) in the measured-z Abell/ACO R \ge 1 clusters sample, we found no significant tendency toward filamentation (axis ratio \ge 3) in comparison with superclusters' in Monte Carlo simulations of random and random-clumped cluster samples. Yet Aquarius and Aquarius-Cetus, in this one region of the sky, have axis ratios of 4.3 and 3.0, respectively.

The Aquarius filament also contains a knot' of six R \ge 1 clusters at z ~0.11, with five of the clusters close enough together to represent an apparent overdensity of 150 \bar{n}. There are three other R \ge 1 cluster density enhancements similar to this knot at lower redshifts: Corona Borealis, the Shapley Concentration, and another grouping of seven clusters that we found in Microscopium. These four superclusters appear near the point of breaking away from the Hubble Flow, and may even be in collapse, but there is little indication of any being virialized. With four such objects, studies of them as a class may now lead to much greater insight into large-scale phenomena.