Isotropy in the two-point angular correlation function of the CMB

Abstract

We study the directional dependence of the angular two-point correlation function in maps of the cosmic microwave background (CMB). We propose two new statistics, one which measures the correlation of each point in the sky with a ring of points separated angle theta away, and a second that measures the missing angular correlation above 60 degrees as a function of direction. Using these statistics, we find that most of the low power in cut-sky maps measured by the WMAP experiment comes from unusually low contributions from the directions of the lobes of the quadrupole and the octupole. These findings may aid a future explanation of why the CMB exhibits low power at large angular scales.

9 pages; adjusted format, edited captions, and added references

References in corpus (5)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results
• The Uncorrelated Universe: Statistical Anisotropy and the Vanishing Angular Correlation Function in WMAP Years 1-3
• Testing a direction-dependent primordial power spectrum with observations of the Cosmic Microwave Background
• The cut-sky cosmic microwave background is not anomalous

Cited by in corpus (3)

• Lack of large-angle TT correlations persists in WMAP and Planck
• Some statistical remarks on the Giant GRB Ring
• Multiverse effects on the CMB angular correlation function in the framework of NCG