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arXiv · 1202.4357

Statistical anisotropy of CMB as a probe of conformal rolling scenario

S. R. Ramazanov·G. I. Rubtsov
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Abstract

Search for the statistical anisotropy in the CMB data is a powerful tool for constraining models of the early Universe. In this paper we focus on the recently proposed cosmological scenario with conformal rolling. We consider two sub-scenarios, one of which involves a long intermediate stage between conformal rolling and conventional hot epoch. Primordial scalar perturbations generated within these sub-scenarios have different direction-dependent power spectra, both characterized by a single parameter h^2. We search for the signatures of this anisotropy in the seven-year WMAP data using quadratic maximum likelihood method, first applied for similar purposes by Hanson and Lewis. We confirm the large quadrupole anisotropy detected in V and W bands, which has been argued to originate from systematic effects rather than from cosmology. We construct an estimator for the parameter h^2. In the case of the sub-scenario with the intermediate stage we set an upper limit h^2 < 0.045 at the 95% confidence level. The constraint on h^2 is much weaker in the case of another sub-scenario, where the intermediate stage is absent.

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S. R. Ramazanov, G. I. Rubtsov. 2012-05-03. Statistical anisotropy of CMB as a probe of conformal rolling scenario. https://doi.org/10.1088/1475-7516%2F2012%2F05%2F033

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