The Omega_M-Omega_Lambda Constraint from CNOC Clusters
  The CNOC redshift survey of galaxy clusters measures Omega_M from Omega_e(z)= M/L x j/\rho_c which can be applied on a cluster-by-cluster basis. The mass-to-light ratios, M/L, are estimated from rich galaxy clusters, corrected to the field population over the 0.18 to 0.55 redshift range. Since the luminosity density depends on cosmological volumes, the resulting Omega_e(z) has a strong dependence on cosmology which allows us to place the results in the Omega_M-Omega_Lambda plane. The resulting Omega_M declines if Omega_Lambda>0 and we find that Omega_Lambda<1.5. 
R. G. Carlberg, H. K. C. Yee, E. Ellingson, S. L. Morris, H. Lin, M.   Sawicki, D. Patton, G. Wirth, R. Abraham, P. Gravel, ...