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Scaling defect decay and the reionization history of the Universe

P. P. Avelino·D. Barbosa
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Abstract

We consider a model for the reionization history of the Universe in which a significant fraction of the observed optical depth is a result of direct reionization by the decay products of a scaling cosmic defect network. We show that such network can make a significant contribution to the reionization history of the Universe even if its energy density is very small (the defect energy density has to be greater than about $10^{-11}$ of the background density). We compute the Cosmic Microwave Background temperature, polarization and temperature-polarization cross power spectrum and show that a contribution to the observed optical depth due to the decay products of a scaling defect network may help to reconcile a high optical depth with a low redshift of complete reionization suggested by quasar data. However, if the energy density of defects is approximately a constant fraction of the background density then these models do not explain the large scale bump in the temperature-polarization cross power spectrum observed by WMAP.

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P. P. Avelino, D. Barbosa. 2004-06-02. Scaling defect decay and the reionization history of the Universe. https://doi.org/10.1103/physrevd.70.067302

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