Statistical anisotropy of CMB as a probe of conformal rolling scenario

TY - JOUR

T1 - Statistical anisotropy of CMB as a probe of conformal rolling scenario

AU - Ramazanov, Sabir

AU - Rubtsov, G.I.

PY - 2012/5/1

Y1 - 2012/5/1

N2 - 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.

AB - 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.

U2 - 10.1088/1475-7516/2012/05/033

DO - 10.1088/1475-7516/2012/05/033

M3 - Journal article

SN - 1475-7516

VL - 2012

SP - 033

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

IS - 5

ER -