Quadrant asymmetry in the angular distribution of cosmic microwave background in the Planck satellite data
Abstract
Some peculiar features found in the angular distribution of the cosmic microwave background (CMB) measured by the Wilkinson Microwave Anisotropy Probe (WMAP) deserve further investigation. Among these peculiar features is the quadrant asymmetry, which is likely related to the northsouth asymmetry. In this paper, we aim to extend the analysis of the quadrant asymmetry in the ΛCDM framework to the Planck foregroundcleaned maps, using the mask provided by Planck team. We compute the twopoint correlation function (TPCF) from each quadrant of the Planck CMB sky maps, and compare the result with 1000 Monte Carlo (MC) simulations generated assuming the ΛCDM bestfit power spectrum. We detect the presence of an excess of power in the southeastern quadrant (SEQ) and a significant lack of power in the northeastern quadrant (NEQ) in the Planck data. Asymmetries between the SEQ and the other three quadrants (southwestern quadrant (SWQ), northwestern quadrant (NWQ), and NEQ) are each in disagreement with an isotropic sky at a 95% confidence level. Furthermore, by rotating the Planck temperature sky map with respect to z direction, we showed the rotation angle where the TPCF of the SEQ has its maximal power. Our analysis of the Planck foregroundcleaned maps shows that there is an excess of power in the TPCF in the SEQ and a significant lack of power in the NEQ when compared with simulations. This asymmetry is anomalous when considering the ΛCDM framework.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 September 2014
 DOI:
 10.1051/00046361/201322943
 arXiv:
 arXiv:1311.0714
 Bibcode:
 2014A&A...569A..75S
 Keywords:

 cosmic background radiation;
 cosmology: observations;
 methods: statistical;
 methods: data analysis;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 Accepted for publication in Astronomy and Astrophysics