Spatial-frequency analysis of the COBE data and the CMB anisotropy spectrum.
Abstract
The problem of obtaining estimates for the cosmic microwave background (CMB) anisotropy spectrum when applying the Galaxy-removal procedure is discussed. A method of two-step spatial-frequency filtering that retains the orthogonality of spherical harmonics is proposed. This method is used to analyze the four-year COBE data. After the analysis of the difference maps containing noise alone, the l = 13,14,23,25 multipoles have been excluded from the data under consideration because the noise power in these multipoles in the difference maps turned out to be statistically anomalous. This procedure is shown to introduce no significant systematic errors for the noise-spectrum model employed. Once the multipoles that are anomalous in terms of noise have been removed, the analysis has yielded a power-law index of the CMB anisotropy power spectrum of n = 1.87±0.25 and a quadrupole mean of Qrms-PS = 13.79±3.0 for 53 GHz, and n = 1.51±0.24 and a quadrupole mean of Qrms-PS = 15.58±2.9 for 90 GHz.
- Publication:
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Microwave Background Anisotropies
- Pub Date:
- 1997
- Bibcode:
- 1997mba..conf...97S
- Keywords:
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- Cosmic Microwave Background: Anisotropy