Cosmic microwave background bispectrum from active models of structure formation - art. no. 043001

We propose a method for a numerical computation of the angular bispectrum o f the cosmic microwave background (CMB) anisotropies arising from active mo dels such as cosmic topological defects, using a modified Boltzmann code ba sed on CMBFAST. The method does not use CMB sky maps and requires moderate computational power. As a first implementation, we apply our method to a re cently proposed model of simulated cosmic strings and estimate the observab ility of the non-Gaussian bispectrum signal. A comparison with the cosmic v ariance of the bispectrum estimator shows that the bispectrum for the simul ated string model we used is not observable.