Book Description

"Cosmic strings are linear concentrations of trapped energy produced throughsymmetry breaking processes of eld theory models. Though they can onlycontribute a maxiumum of 10 percent to structure formation they have beenshown to arise as a generic consequence of many inationary setups of supergravitymodels. In addition they provide another avenue to probe physicsbeyond the "Standard Model". Cosmic strings can intersect producing stringloops. These topological defects are formed at early times creating largeamounts of accretion and thus lead to large amounts of baryon overdensities.These baryonic overdensities of hydrogen lead to a unique 21cm signature.We focus on cosmic string loops in addition to global monopoles and computethe 21cm signature produced by these structures. It is found that both defectsproduce an elliptical region in 21cm radiation maps with a large emissionsignal which may serve as a prediction for upcoming 21cm redshift surveys." --