V/Vmax statistic and Neo-Classic Cosmological Tests

Abstract

A new cosmological test is derived, based on the distribution of individual V/Vmax in a complete redshift-limited sample of distant objects. The fundamental assumption is that, in any bin of absolute luminosity, individual V/Vmax are required to be uniformly spread over the [0,1] range. This condition of uniformity allows a likelihood function to be computed from the Kolmogorov- Smirnov probabilities of each bin. Monte-Carlo simulations show that the test is mostly sensitive to the density parameter, but under certain conditions, it also sets constraints on the space curvature and, to a lower extent, on the cosmological constant. The test is then applied to the UVX sample of Boyle et al. (1990). A low matter density, and a flat Universe without cosmological constant, are rejected: 0.2<Omega<0.8 within the 95% confidence level.