Evidence for filamentarity in the Las Campanas Redshift Survey

We apply Shapefinders, statistical measures of "shape" constructed from two -dimensional partial Minkowski functionals, to study the degree of filament arity in the Las Campanas Redshift Survey (LCRS). In two dimensions, three Minkowski functionals characterize the morphology of an object; these are i ts perimeter (L), area (S), and genus. Out of L and S a single dimensionles s Shapefinder statistic, F, can be constructed (0 less than or equal to F l ess than or equal to 1). The statistic F acquires extreme values on a circl e (F = 0) and a filament (F = 1). Using F, we quantify the extent of filame ntarity in the LCRS by comparing our results with a Poisson distribution ha ving similar geometrical properties and the same selection function as the survey. Our results unambiguously demonstrate that the LCRS displays a high degree of filamentarity in both the northern and southern Galactic section s, in general agreement with the visual appearance of the catalog. It is we ll known that gravitational clustering from Gaussian initial conditions giv es rise to the development of non-Gaussianity, reflected in the formation o f a network-like filamentary structure on supercluster scales. Consequently , the fact that the smoothed LCRS catalog shows properties consistent with those of a Gaussian random field, whereas the unsmoothed catalog demonstrat es the presence of filamentarity, lends strong support to the conjecture th at the large-scale clustering of galaxies is driven by gravitational instab ility.