The bull's-eye effect as a probe of Ω

We compare the statistical properties of structures normal and transverse to the line of sight that appear in theoretical N-body simulations of structure formation and also seem to be present in observational data from redshift surveys. We present a statistic that can quantify this effect in a conceptually different way from standard analyses of distortions of the power spectrum or correlation function. From tests with N-body experiments, we argue that this statistic represents a new and potentially powerful diagnostic of the cosmological density parameter, Omega.