The cut-sky cosmic microwave background is not anomalous

Journal Article · Sat May 15 00:00:00 EDT 2010 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.81.103008· OSTI ID:21413441

Pontzen, Andrew ^[1]; Peiris, Hiranya V ^[1]

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1. Institute of Astronomy and Kavli Institute for Cosmology, University of Cambridge, Cambridge CB3 0HA (United Kingdom)

The observed angular correlation function of the cosmic microwave background has previously been reported to be anomalous, particularly when measured in regions of the sky uncontaminated by Galactic emission. Recent work by Efstathiou et al. presents a Bayesian comparison of isotropic theories, casting doubt on the significance of the purported anomaly. We extend this analysis to all anisotropic Gaussian theories with vanishing mean (<{delta}T>=0), using the much wider class of models to confirm that the anomaly is not likely to point to new physics. On the other hand if there is any new physics to be gleaned, it results from low-l alignments which will be better quantified by a full-sky statistic. We also consider quadratic maximum likelihood power spectrum estimators that are constructed assuming isotropy. The underlying assumptions are therefore false if the ensemble is anisotropic. Nonetheless we demonstrate that, for theories compatible with the observed sky, these estimators (while no longer optimal) remain statistically superior to pseudo-C{sub l} power spectrum estimators.

• OSTI ID: 21413441
• Journal Information: Physical Review. D, Particles Fields, Vol. 81, Issue 10; Other Information: DOI: 10.1103/PhysRevD.81.103008; (c) 2010 The American Physical Society; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ANGULAR CORRELATION
ANISOTROPY
COMPARATIVE EVALUATIONS
CORRELATION FUNCTIONS
EMISSION
ISOTROPY
MAXIMUM-LIKELIHOOD FIT
RELICT RADIATION
SIMULATION
SPECTRA
CORRELATIONS
ELECTROMAGNETIC RADIATION
EVALUATION
FUNCTIONS
MATHEMATICAL SOLUTIONS
MICROWAVE RADIATION
NUMERICAL SOLUTION
RADIATIONS