1203.5720 (Hao Liu et al.)

Missing completely of CMB quadrupole in WMAP data    [PDF]

Hao Liu, Ti-Pei Li

In cosmic microwave background (CMB) experiments, foreground-cleaned temperature maps are still disturbed by the dipole contamination caused by uncertainties of the dipole direction and microwave radiometer sidelobe. To obtain reliable CMB maps, the dipole contamination has to be carefully removed from observed data. We built and improve a software package for map-making with dipole-contamination removing, and power spectrum estimation form the Wilkinson Microwave Anisotropy Probe (WMAP) data. With the software we obtain a negative result of CMB quadrupole detection with WMAP data, the amplitude of CMB quadrupole is -3.2\pm3.5 {\mu}K^2 from the seven-year WMAP (WMAP7) data, which is evidently incompatible with \sim1000 {\mu}K^2 expected from the standard cosmological model LCDM. The completely missing of CMB quadrupole poses a serious challenge to the standard model and sets a strong constraint on possible models of cosmology. Due to the importance of this result for understanding the origin and early evolution of our universe, the software codes we used are opened for public checking.

View original: http://arxiv.org/abs/1203.5720