Query : 2006A&A...454..409B

2006A&A...454..409B - Astronomy and Astrophysics, volume 454, 409-414 (2006/8-1)

On the cosmic microwave background large-scale angular correlations.


Abstract (from CDS):

We study the large-scale angular correlation signatures of the cosmic microwave background (CMB) temperature fluctuations from WMAP data in several spherical cap regions of the celestial sphere, outside the Kp0 or Kp2 cut-sky masks. We applied a recently proposed method to CMB temperature maps to permit an accurate analysis of their angular correlations in the celestial sphere through the use of normalized histograms of the number of pairs of such objects with a given angular separation versus their angular separation. The method allows for a better comparison of the results from observational data with the expected CMB angular correlations of a statistically isotropic universe, computed from Monte-Carlo maps according to the WMAP best-fit ΛCDM model. We found that the already known, anomalous lack of large-scale power in full-sky CMB maps is mainly due to deficient angular correlations of a quadrupole-like signature. This result is robust with respect to frequency CMB maps and cut-sky masks. Moreover, we also confirm previous results regarding the uneven distribution in the sky of the large-scale power of WMAP data. In a bin-to-bin correlation analyses, measured by the full covariance matrix χ2 statistic, we found that the angular correlation signatures in opposite Galactic hemispheres are anomalous at a 98%-99% confidence level.

Abstract Copyright:

Journal keyword(s): cosmology: large-scale structure of Universe - cosmic microwave background - cosmology: observations

Simbad objects: 2

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Number of rows : 2
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 NAME SGP reg 00 51 26.275 -27 07 41.70           ~ 561 0
2 NAME NGP reg 12 51 26.275 +27 07 41.70           ~ 1148 0

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