Signatures of Topological Defects in the Microwave Sky: An Introduction

TL;DR

This paper introduces topological defects in cosmology, focusing on their signatures in the cosmic microwave background anisotropies and comparing their effects with inflationary models.

Contribution

It provides an overview of topological defects' potential role in structure formation and analyzes their signatures in the CMB spectrum with simple analytic estimates.

Findings

Topological defects produce distinctive signatures in the CMB anisotropy spectrum.

Analytic estimates show differences between defect-induced and inflationary perturbations.

Comparison highlights potential observational distinctions between models.

Abstract

An introduction to topological defects in cosmology is given. We discuss their possible relevance for structure formation. Especial emphasis is given on the signature of topological defects in the spectrum of anisotropies in the cosmic microwave background. We present simple analytic estimates for the CMB spectrum on large and intermediate scales and compare them with the corresponding approximations for models where initial perturbations are generated during an inflationary epoch.