COBE Data Spatial--Frequency Analysis and CMB Anisotropy Spectrum

Abstract

We discuss the problem of CMB spectrum corruption during Galactic emission removing. A new technique of spatial--frequency data reduction is proposed. The technique gives us a possibility to avoid a spatial harmonics nonorthogonality. The proposed technique is applied to the two-year COBE DMR sky maps. We exclude the harmonics with l=7, 9,13, 23 and 25 as having anomalous statistics noise behavior. One shows that procedure do not give systematic errors, if the data are statistically regular. The spectral parameter of the power spectrum of primordial perturbation $n=1.84 \pm 0.29$ and quadrupole moment $Q_2=15.22 \pm 3.0$ are estimated. The power spectrum estimation results are inconsistent with the Harrison-Zel`dovich $n=1$ model with the confidence 99%. It is shown a necessity of an increasing a survey sensitivity to reach a more reliable estimation of the cosmological signal.