Abundances and correlations of structures beyond galaxy clusters

We investigated the structures on scales beyond the typical clusters of gal axies. These structures are crucial to understanding the cosmic gravitation al clustering in the previrialized stage, or quasi-linear regime. Based on the multiresolution analysis of the discrete wavelet transformation, we obt ained statistically available ensembles of r(cl) clusters, i.e., the struct ures on scale r(cl), in the range of 1 less than or equal to r(cl) less tha n or equal to 24 h(-l) Mpc for both N-body simulation and the IRAS 1.2 Jy g alaxy survey samples. When the mass-to-light ratio (M/L) on scales larger t han that of the clusters asymptotically reaches a constant, we found that t he abundances and correlations of these IRAS r(cl) clusters were basically consistent with the predictions of the flat low-density CDM model (OCDM) an d the open CDM model (OCDM), except that the model-predicted abundance of r (cl) = 24 h(-l) Mpc clusters seems to be higher than that predicted by the IRAS data. The standard CDM (SCDM) gives too much power and provides correl ations that are too weak on all the scales. For a given r(cl), the amplitud e of the two-point correlation function of r(cl), clusters increases with t heir richness. However, for a given richness (defined by the mean separatio n of neighboring objects), the clustering strengths of both the simulation and observation samples decline with r(cl) when r(cl) is larger than 3-4 h( -l) Mpc. Therefore, the "universal" increase of the correlation amplitude w ith the scale of objects from galaxies, groups, to poor, rich clusters is b roken down for structures of r(cl) > 3-4 h(-l) Mpc. Superclusters should no t be members of the " universal" increase family.