CMB Anisotropies by Collapsing Textures
Topological defects are generically formed in many interesting cosmological scenarios, such as those based in Grand Unified Theories and Superstrings. These defects would produce an observable effect on the Cosmic Microwave Background (CMB), and in particular, collapsing texture knots would generate hot and cold spots in the CMB. Bayesian statistical analysis shows that the observed "Cold Spot" of the CMB is compatible with the imprint left by one of such a collapsing textures. These studies rely on the anisotropy pattern produced by a collapsing texture under very controlled conditions: spherical symmetry, self-similar collapse, and the non-linear sigma model approximation of the field dynamics. We evolve numerically the true field dynamics in an expanding universe, and we calculate the anisotropy pattern left by a collapsing texture with random initial conditions.