Filaments and Pancakes in the [ITAL]IRAS[/ITAL] 1.2 J[CLC]y[/CLC] Redshift Catalog

Abstract

We explore shapes of clusters and superclusters in the IRAS 1.2Jy redshift survey with three reconstructions spanning the range β = 0.1, 0.5, 1.0, where β = Ω 0.6 /b, b is the bias factor and Ω the present value of the dimensionless matter density. Comparing our results to Gaussian randomized reconstructions of the IRAS catalogue, we find structures having both planar and filamentary properties. For β = 0.5, 1.0 the largest structures in the survey have a distinct tendency to be filament-like in general agreement with the results of N-body simulations.

PSCz superclusters: detection, shapes and cosmological implications

“…It is obvious that the dominant feature of the PSC z superclusters (for all β ) is the filamentary type structure, i.e. [in agreement with previous studies; see Sathyaprakash et al (1998a,b)]. We see only a weak tendency to have less filamentary superclusters for reconstructions with…”

“…West (1989), Plionis, Valdarnini & Jing (1992) and Jaaniste et al (1997) studied the morphological properties (shape, size and orientation) of galaxy superclusters using ACO clusters and found, based on the simple principal axes method, that the vast majority of the superclusters are flattened triaxial objects, while Plionis et al (1992) found a predominance of prolate (filament‐like) superclusters. Further support to the filamentary case was presented recently by Sathyaprakash et al (1998a,b) who analysed the shapes of the overdense regions using observational ( IRAS 1.2 Jy) and N ‐body simulation data.…”

The Size of the Longest Filaments in the Universe

“…2 One of the first morphological survey of the real universe was done by Sathyaprakash et al (1998), who analyzed the 1.2 Jy Redshift Survey Catalog. physical filaments of lengths greater than L. We use three realizations for L ¼ 10; 20; 30; 90, and 100 h À1 Mpc shuffling of slices and six realizations for the intermediate length scales.…”

Pancakes and filaments in cosmological gravitational clustering

“…N-body simulations of structure formation indicate that as gravitational instability advances the filling factor decreases as more matter gets concentrated in filaments and pancakes [13,10]. Analysis of three dimensional catalogues, although very preliminary, appears to suport this viewpoint as shown in figure 2 [14]. The two dimensional shapefinder statistic can also be …”

“…For more details see Sathyaprakash et al [14]. used to study the shapes of hot and cold spots in the cosmic microwave background and the shapes of gravitationally lensed quasars and galaxies.…”