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Joint Bayesian component separation and CMB power spectrum estimation

Show simple item record Eriksen, H. K. Jewell, J. B. Dickinson, C. Banday, A. J. Gorski, K. M. Lawrence, C. R. 2008-07-28T22:46:32Z 2008-07-28T22:46:32Z 2008-03-20
dc.identifier.citation The Astrophysical Journal, 676:10Y32, 2008 March 20, en_US
dc.identifier.clearanceno 08-0423
dc.description.abstract We describe and implement an exact, flexible, and computationally efficient algorithm for joint component separation and CMB power spectrum estimation, building on a Gibbs sampling framework. Two essential new features are (1) conditional sampling of foreground spectral parameters and (2) joint sampling of all amplitude-type degrees of freedom (e.g., CMB, foreground pixel amplitudes, and global template amplitudes) given spectral parameters. Given a parametric model of the foreground signals, we estimate efficiently and accurately the exact joint foreground- CMB posterior distribution and, therefore, all marginal distributions such as the CMB power spectrum or foreground spectral index posteriors. The main limitation of the current implementation is the requirement of identical beam responses at all frequencies, which restricts the analysis to the lowest resolution of a given experiment. We outline a future generalization to multiresolution observations. To verify the method, we analyze simple models and compare the results to analytical predictions. We then analyze a realistic simulation with properties similar to the 3 yr WMAP data, downgraded to a common resolution of 3ºFWHM. The results from the actual 3 yr WMAP temperature analysis are presented in a companion Letter. en_US
dc.description.sponsorship NASA/JPL en_US
dc.language.iso en_US en_US
dc.publisher The American Astronomical Society en_US
dc.subject cosmic microwave background en_US
dc.subject observations en_US
dc.subject numerical en_US
dc.title Joint Bayesian component separation and CMB power spectrum estimation en_US
dc.type Article en_US

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