The angular power spectrum of the 4 year COBE data

Abstract

The angular power spectrum C_l is extracted from the 4 year COBE DMR data with a 20 degree galactic cut, using the narrowest window functions possible. The average power in eight multipole bands is also computed, and plotted together with a compilation of power spectrum measurements from other experiments. The COBE results are found to be consistent with an n=1 power spectrum with the normalization Qrmsps=18 microkelvin reported by the COBE DMR team. Certain non-standard cosmologies, such as "small universe" models with nontrivial spatial topology, predict power spectra which are not smooth functions. Rather, they contain bumps and wiggles that may not have been detected by other data analysis techniques such as the Hauser-Peebles method (Wright etal 1996), the band-power method (Hinshaw etal 1996) and orthogonalized spherical harmonics (Gorski etal 1996), since these methods all give broader window functions that can smear such features out beyond recognition. On the large angular scales probed by COBE, the Universe thus appears to be kind to us, presenting a power spectrum that is a simple smooth function.

Final accepted version, incl. plots with new Saskatoon data. 14 pages, with 4 figures included. Postscript. Latest version at http://www.sns.ias.edu/~max/cobepow.html (faster from the US), from http://www.mpa-garching.mpg.de/~max/cobepow.html (faster from Europe) or from [email protected]

References in corpus (16)

• 4-Year COBE DMR Cosmic Microwave Background Observations: Maps and Basic Results
• Cosmic Background Anisotropies in CDM Cosmology
• Microwave Emission at High Galactic Latitudes
• Power Spectrum of Primordial Inhomogeneity Determined from the 4-Year COBE DMR Sky Maps
• Weighing the Universe with the Cosmic Microwave Background
• On Determining the Spectrum of Primordial Inhomogeneity from the COBE DMR Sky Maps: I. Method
• A brute force analysis of the COBE DMR data
• Signal-to-Noise Eigenmode Analysis of the Two-Year COBE Maps
• From Microwave Anisotropies to Cosmology
• Band Power Spectra in the COBE DMR 4-Year Anisotropy Maps
• Angular Power Spectrum of the Microwave Background Anisotropy seen by the COBE Differential Microwave Radiometer
• Constraints on the topology of the universe from the 2-yr COBE data
• Cosmological-Constant Cold Dark Matter Models and the COBE Two-Year Sky maps
• The COBE Normalization of CMB Anisotropies
• The Amplitude and Spectral Index of the Large Angular Scale Anisotropy in the Cosmic Microwave Background Radiation
• A method for extracting maximum resolution power spectra from microwave sky maps

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