COSMOLOGICAL CONSTANT COLD DARK-MATTER MODELS AND THE COBE 2-YEAR SKY MAPS

We compare the 2 yr COBE DMR sky maps with the predictions of cosmological constant cold dark matter (lambda CDM) models. Using a Bayesian analysis, we find that the most likely value of the cosmological constant in a lambda CDM model is lambda = O. The data set an upper limit on lambda of 0.78 (0.85) at 90% confidence, and 0.86 (0.92) at 95% confidence with (without) the quadrupole anisotropy. The angular power spectrum C-l depends only quadratically on lambda when lambda is small; the likelihood function L lambda is therefore quite flat near lambda = 0.