Evidence against or for topological defects in the BOOMERanG data ?

Abstract

The recently released BOOMERanG data was taken as ``contradicting topological defect predictions''. We show that such a statement is partly misleading. Indeed, the presence of a series of acoustic peaks is perfectly compatible with a non-negligible topological defects contribution. In such a mixed perturbation model (inflation and topological defects) for the source of primordial fluctuations, the natural prediction is a slightly lower amplitude for the Doppler peaks, a feature shared by many other purely inflationary models. Thus, for the moment, it seems difficult to rule out these models with the current data.