Missing completely of CMB quadrupole in WMAP data

TL;DR

This study reanalyzed WMAP data with improved software, finding a missing CMB quadrupole inconsistent with standard cosmological expectations, challenging current models of the universe.

Contribution

The paper presents an improved software package for CMB data analysis and reports a null detection of the quadrupole, questioning standard cosmological models.

Findings

CMB quadrupole detected as negative value (-3.2±3.5 μK²)

Result incompatible with expected ~1000 μK² from LCDM model

Software codes are publicly available for verification

Abstract

In cosmic microwave background (CMB) experiments, foreground-cleaned temperature maps are still contaminated by the residual dipole due to uncertainties of the Doppler dipole direction and microwave radiometer sidelobe. To obtain reliable CMB maps, such contamination has to be carefully removed from observed data. We have previously built a software package for map-making, residual dipole-contamination removal, and power spectrum estimation from the Wilkinson Microwave Anisotropy Probe (WMAP) raw data. This software has now been significantly improved. With the improved software, we obtain a negative result of CMB quadrupole detection with the WMAP raw data, which is -3.2+-3.5 uK^2 from the seven-year WMAP (WMAP7) data. This result is evidently incompatible with ~1000 uK^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.