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Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Are There Cosmic Microwave Background Anomalies?

Authors :
Eiichiro Komatsu
Gregory S. Tucker
Mark Halpern
Janet L. Weiland
David N. Spergel
N. Odegard
Lyman A. Page
Kristine M. Smith
Edward J. Wollack
Michele Limon
Edward L. Wright
Alan J. Kogut
Robert S. Hill
Charles L. Bennett
B. Gold
Jo Dunkley
Gary Hinshaw
N. Jarosik
Michael R. Nolta
S. S. Meyer
Davin Larson
Source :
The Astrophysical Journal Supplement Series
Publication Year :
2016

Abstract

(Abridged) A simple six-parameter LCDM model provides a successful fit to WMAP data, both when the data are analyzed alone and in combination with other cosmological data. Even so, it is appropriate to search for any hints of deviations from the now standard model of cosmology, which includes inflation, dark energy, dark matter, baryons, and neutrinos. The cosmological community has subjected the WMAP data to extensive and varied analyses. While there is widespread agreement as to the overall success of the six-parameter LCDM model, various "anomalies" have been reported relative to that model. In this paper we examine potential anomalies and present analyses and assessments of their significance. In most cases we find that claimed anomalies depend on posterior selection of some aspect or subset of the data. Compared with sky simulations based on the best fit model, one can select for low probability features of the WMAP data. Low probability features are expected, but it is not usually straightforward to determine whether any particular low probability feature is the result of the a posteriori selection or of non-standard cosmology. We examine in detail the properties of the power spectrum with respect to the LCDM model. We examine several potential or previously claimed anomalies in the sky maps and power spectra, including cold spots, low quadrupole power, quadropole-octupole alignment, hemispherical or dipole power asymmetry, and quadrupole power asymmetry. We conclude that there is no compelling evidence for deviations from the LCDM model, which is generally an acceptable statistical fit to WMAP and other cosmological data.<br />19 pages, 17 figures, also available with higher-res figures on http://lambda.gsfc.nasa.gov; accepted by ApJS; (v2) text as accepted

Details

Language :
English
Database :
OpenAIRE
Journal :
The Astrophysical Journal Supplement Series
Accession number :
edsair.doi.dedup.....8fceb5b2d659cd8eccc8909adc15cde6
Full Text :
https://doi.org/10.1088/0067-0049/192/2/17