Hemispherical Power Asymmetry from a Space-Dependent Component of the Adiabatic Power Spectrum

Abstract

The hemispherical power asymmetry observed by Planck and WMAP can be interpreted as due to a spatially-varying and scale-dependent component of the adiabatic power spectrum. We derive general constraints on the magnitude and scale-dependence of a component with a dipole spatial variation. The spectral index and the running of the spectral index can be significantly shifted from their inflation model values, resulting in a smaller spectral index and a more positive running. A key prediction is a hemispherical asymmetry of the spectral index and of its running. Measurement of these asymmetries can test the structure of the perturbation responsible for the CMB power asymmetry.

5 pages. Additional discussion, improved observational bound on the scale-dependence of the asymmetry. Version to be published

References in corpus (6)

• Hemispherical power asymmetry in the three-year Wilkinson Microwave Anisotropy Probe sky maps
• A Hemispherical Power Asymmetry from Inflation
• Power asymmetry in WMAP and Planck temperature sky maps as measured by a local variance estimator
• Superhorizon Perturbations and the Cosmic Microwave Background
• Constraints on cosmic hemispherical power anomalies from quasars
• A Scale-Dependent Power Asymmetry from Isocurvature Perturbations

Cited by in corpus (9)

• CMB Hemispherical Asymmetry: Long Mode Modulation and non-Gaussianity
• Pre-inflationary primordial perturbations
• A paradigm of warm quintessential inflation and production of relic gravity waves
• Joint Planck and WMAP Assessment of Low CMB Multipoles
• Expected dipole asymmetry in CMB polarization
• CMB hemispherical asymmetry from non-linear isocurvature perturbations
• Generating $\fnl$ at $\ell\lsim 60$
• Negative Running of the Spectral Index, Hemispherical Asymmetry and the Consistency of Planck with Large $r$
• CMB Polarization by the Asymmetric Template of Scalar Perturbations