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arXiv · 1003.5548

Cosmic microwave background constraints on cosmological models with large-scale isotropy breaking

Haoxuan Zheng·Emory F. Bunn
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Abstract

Several anomalies appear to be present in the large-angle cosmic microwave background (CMB) anisotropy maps of WMAP, including the alignment of large-scale multipoles. Models in which isotropy is spontaneously broken (e.g., by a scalar field) have been proposed as explanations for these anomalies, as have models in which a preferred direction is imposed during inflation. We examine models inspired by these, in which isotropy is broken by a multiplicative factor with dipole and/or quadrupole terms. We evaluate the evidence provided by the multipole alignment using a Bayesian framework, finding that the evidence in favor of the model is generally weak. We also compute approximate changes in estimated cosmological parameters in the broken-isotropy models. Only the overall normalization of the power spectrum is modified significantly.

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Haoxuan Zheng, Emory F. Bunn. 2010-09-02. Cosmic microwave background constraints on cosmological models with large-scale isotropy breaking. https://doi.org/10.1103/physrevd.82.063533

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