Detailed study of defect models for cosmic structure formation

Abstract

We calculate predictions from wide class of `active' models of cosmic\nstructure formation which allows us to scan the space of possible defect\nmodels. We calculate the linear cold dark matter power spectrum and Cosmic\nMicrowave Background (CMB) anisotropies over all observable scales using a full\nlinear Einstein-Boltzmann code. Our main result, which has already been\nreported, points to a serious problem reconciling the observed amplitude of the\nlarge-scale galaxy distribution with the COBE normalization. Here, we describe\nour methods and results in detail. The problem is present for a wide range of\ndefect parameters, which can be used to represent potential differences among\ndefect models, as well as possible systematic numerical errors. We explicitly\nexamine the impact of varying the defect model parameters and we show how the\nresults substantiate these conclusions. The standard scaling defect models are\nin serious conflict with the current data, and we show how attempts to resolve\nthe problem by considering non-scaling defects or modified stress-energy\ncomponents would require radical departures from what has become the standard\npicture.\n

Keywords

Affiliated Institutions

• University of California, Berkeley US
• Imperial College London GB
• SKA Observatory GB

Related Publications