Local variance asymmetries in Planck temperature anisotropy maps

Abstract

Recently, it was shown that local variance maps of temperature anisotropy are simple and useful tools for the study of large scale hemispherical power asymmetry. This was done by studying the distribution of dipoles of the local variance maps. In this work, we extend the study of the dipolar asymmetry in local variance maps using foreground cleaned Planck 143 GHz and 217 GHz data to smaller scales. In doing so, we include the effect of the CMB Doppler dipole. Further, we show that it is possible to use local variance maps to measure the Doppler dipole in these Planck channel maps, after removing large scale features (up to $l=600$), at a significance of about $3\sigma$. At these small scales, we do not find any power asymmetry in the direction of the anomalous large scale power asymmetry beyond that expected from cosmic variance. At large scales, we verify previous results i.e. the presence of hemispherical power asymmetry at a significance of at least $3.3\sigma$.

7 pages and 7 figures; various typos fixed and discussions clarified in v2 to match the MNRAS accepted version

References in corpus (7)

• 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
• Constraints on cosmic hemispherical power anomalies from quasars
• A Scale-Dependent Power Asymmetry from Isocurvature Perturbations
• The Signature of Proper Motion in the Microwave Sky
• Linking the BICEP2 result and the hemispherical power asymmetry through spatial variation of $r$

Cited by in corpus (4)

• Expected dipole asymmetry in CMB polarization
• CMB hemispherical asymmetry from non-linear isocurvature perturbations
• Strongly scale-dependent CMB dipolar asymmetry from super-curvature fluctuations
• Testing cosmological models with large-scale power modulation using microwave background polarization observations