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Joint Bayesian Component Separation and CMB Power Spectrum Estimation

Eriksen, H. K. and Jewell, J. B. and Dickinson, C. and Banday, A. J. and Górski, K. M. and Lawrence, C. R. (2008) Joint Bayesian Component Separation and CMB Power Spectrum Estimation. Astrophysical Journal, 676 (1). pp. 10-32. ISSN 0004-637X. doi:10.1086/525277.

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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 3° FWHM. The results from the actual 3 yr WMAP temperature analysis are presented in a companion Letter.

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Dickinson, C.0000-0002-0045-442X
Additional Information:© 2008. The American Astronomical Society. Received 2007 September 7; accepted 2007 November 3; published 2008 March 20. Print publication: Issue 1 (2008 March 20). We acknowledge use of the HEALPix software (Górski et al. 2005) and analysis package for deriving the results in this paper. We acknowledge use of the Legacy Archive for Microwave Background Data Analysis (LAMBDA). This work was partially performed at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. H.K.E. acknowledges financial support from the Research Council of Norway and the hospitality of the Center for Long Wavelength Astrophysics at JPL.
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Research Council of NorwayUNSPECIFIED
Subject Keywords:cosmic microwave background; cosmology: observations; methods: numerical
Issue or Number:1
Record Number:CaltechAUTHORS:ERIapj08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13008
Deposited By: Archive Administrator
Deposited On:15 Jan 2009 05:50
Last Modified:08 Nov 2021 22:34

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