Statistical anisotropy of CMB as a probe of conformal rolling scenario
- Niels Bohr International Academy and Discovery Center, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100, Copenhagen (Denmark)
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{sup 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{sup 2}. In the case of the sub-scenario with the intermediate stage we set an upper limit h{sup 2} < 0.045 at the 95% confidence level. The constraint on h{sup 2} is much weaker in the case of another sub-scenario, where the intermediate stage is absent.
- OSTI ID:
- 22279793
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2012, Issue 05; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
Similar Records
Conformal invariance, dark energy, and CMB non-gaussianity
Scalar perturbations in conformal rolling scenario with intermediate stage