Cosmic microwave background anisotropies from scaling seeds: Global defectmodels - art. no. 123005

We investigate the global texture model of structure formation in cosmogoni es with a nonzero cosmological constant for different values of the Hubble parameter. We find that the absence of significant acoustic peaks and littl e power on large scales are robust predictions of these models. However, fr om a cartful comparison with data we conclude that at present we cannot saf ely reject the model on the grounds of present CMB data, Exclusion by means of galaxy correlation data requires assumptions on biasing and statistics. New, very stringent constraints come from peculiar velocities. Investigati ng the large-N limit, we argue that our main conclusions apply to all globa l O(N) models of structure formation. [S0556-2821(99)07312-9].