LACK OF ANGULAR CORRELATION AND ODD-PARITY PREFERENCE IN COSMIC MICROWAVE BACKGROUND DATA

We have investigated the angular correlation in the recent cosmic microwave background data. In addition to the known large-angle correlation anomaly, we find the lack of correlation at small angles with high statistical significance. We have investigated various non-cosmological contamination as well as the Wilkinson Microwave Anisotropy Probe (WMAP) team's simulated data. However, we have not found a definite cause. In the angular power spectrum of WMAP data, there exists anomalous odd-parity preference at low multipoles. Noting the equivalence between the power spectrum and the correlation, we have investigated the association between the lack of large-angle correlation and the odd-parity preference. From our investigation, we find that the odd-parity preference at low multipoles is, in fact, a phenomenological origin of the lack of large-angle correlation. Further investigation is required to find out whether the origin of the anomaly is cosmological or due to unaccounted systematics. The data from the Planck surveyor, which has systematics distinct from WMAP, will greatly help us to resolve its origin.