Power Spectra in Global Defect Theories of Cosmic Structure Formation

An efficient technique for computing perturbation power spectra in field ordering theories of cosmic structure formation is introduced, enabling computations to be carried out with unprecedented precision. Microwave anisotropy and matter perturbation power spectra for global strings, monopoles, textures, and nontopological textures are presented and compared with recent observations. The most striking results are (a) the absence of pronounced peaks in the $C_l$ anisotropy power spectrum and (b) the lack of large scale power in the matter power spectrum.