Cosmic Microwave Background Statistics for a Direction-Dependent Primordial Power Spectrum

By A. Pullen, M. Kamionkowski. 2007

177 citations recorded by the source corpus.

Statistical isotropy of primordial perturbations is a common assumption in cosmology, but it is an assumption that should be tested. To this end, we develop cosmic microwave background statistics for a primordial power spectrum that depends on the direction, as well as the magnitude, of the Fourier wave vector. We first consider a simple estimator that searches in a model-independent way for anisotropy in the square of the temperature (and/or polarization) fluctuation. We then construct the minimum-variance estimators for the coefficients of a spherical-harmonic expansion of the directional dependence of the primordial power spectrum. To illustrate, we apply these statistics to an inflation model with a quadrupole dependence of the primordial power spectrum on direction and find that a power quadrupole as small as 2.0% can be detected with the Planck satellite.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics, Oceanography

View Paper: https://www.semanticscholar.org/paper/98795071112d624d25003df237e8e7468192ebea

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In Astronomy and Astrophysics

1. E. Komatsu
2. A. Banday
3. Andrey V. Kravtsov
4. K. G'orski
5. H. Eriksen
6. Simon D. M. White
7. Volker Springel
8. David N. Spergel

In Nuclear and High Energy Physics

1. E. Komatsu
2. Lavinia Heisenberg
3. D. Schwarz
4. A. Banday
5. David N. Spergel
6. Mark Halpern
7. C. Bennett
8. Andrey V. Kravtsov

In Oceanography

1. F. Hansen
2. A. Banday
3. H. Eriksen
4. K. G'orski
5. P. Lilje
6. J. Hoftuft
7. Lavinia Heisenberg
8. C. Porciani

Citations in the corpus

• Large-Angle Anomalies in the CMB (2010, background): “For example, a convenient approach is to describe the breaking of isotropy via the direction-dependent power spectrum of dark matter perturbations [82]”
• Cosmology and Fundamental Physics with the Euclid Satellite (2012, background): “Planck should be able to detect a power quadrupole as small as 2% (at 3σ ) (Pullen and Kamionkowski 2007; Groeneboom and Eriksen 2009; Groeneboom et al. 2010).”
• Vector field models of inflation and dark energy (2008, unknown): “Contents”
• INCREASING EVIDENCE FOR HEMISPHERICAL POWER ASYMMETRY IN THE FIVE-YEAR WMAP DATA (2009, background): “…Gümrükçüoglu et al. 2007; Himmetoglu et al. 2008a,b; Kahniashvili et al. 2008; Kanno et al. 2008; Koivisto & Mota 2008a,b; Pereira et al. 2007; Pitrou et al. 2008; Pullen & Kamionkowski 2007; Watanabe et al. 2009; Yokoyama & Soda 2008), but so far no fully convincing model has been established.”
• Gauge fields and inflation (2012, background): “These observational signature, although their statistical significance is still controversial [41], stimulated activity in the research of statistical anisotropy [42, 43, 44, 45, 46, 47, 48, 49, 50, 51].”
• SEVEN-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP ) OBSERVATIONS: ARE THERE COSMIC MICROWAVE BACKGROUND ANOMALIES? (2010, background): “Optimal estimators had previously been constructed in the all-sky case by Pullen & Kamionkowski (2007) and Dvorkin et al. (2008).”