Genus statistics on CMB polarization maps and cosmological parameter degeneracy

We apply genus statistics to simulated CMB polarization maps, constructed from secondary-ionization cosmological models in experimental situations comparable to those of forthcoming space experiments. We find that both the cosmic baryon density and the spectral index of density perturbations are strongly anticorrelated to the reionization redshift. Using the Fisher matrix approach we show that the accuracies in determining the spectral index and the optical depth to the reionization epoch are better in the case of genus statistics than in standard power spectrum statistics. (C) 1999 Elsevier Science B. V. All rights reserved.