Topological Defect Models of Structure Formation after the Cobe Discovery of Cmb Anisotropies

The COBE satellite has discovered anisotropies in the cosmic microwave background (CMB) consistent with a scale invariant spectrum of density perturbations1). As reviewed in this lecture, topological defect models of structure formation generically produce such a spectrum. We give a summary of the cosmic string and global texture models, focusing on distinct observational signatures in large-scale structure surveys and in the microwave background. It is shown that the amplitude of the CMB quadrupole detected by COBE is in good agreement with the predictions of the cosmic string model.2,3) ⋆ Invited lecture at the International School of Astrophysics “D. Chalonge,” 2nd course, 6-13 Sept., 1992, Erice, Italy, to be published in the proceedings (World Scientific, Singapore, 1992).