A Caltech Library Service

Bayesian Component Separation and Cosmic Microwave Background Estimation for the Five-Year WMAP Temperature Data

Dickinson, C. and Eriksen, H. K. and Banday, A. J. and Jewell, J. B. and Górski, K. M. and Huey, G. and Lawrence, C. R. and O'Dwyer, I. J. and Wandelt, B. D. (2009) Bayesian Component Separation and Cosmic Microwave Background Estimation for the Five-Year WMAP Temperature Data. Astrophysical Journal, 705 (2). pp. 1607-1623. ISSN 0004-637X.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


A well-tested and validated Gibbs sampling code, that performs component separation and cosmic microwave background (CMB) power spectrum estimation, was applied to the WMAP five-year data. Using a simple model consisting of CMB, noise, monopoles, and dipoles, a "per pixel" low-frequency power-law (fitting for both amplitude and spectral index), and a thermal dust template with a fixed spectral index, we found that the low-ℓ (ℓ < 50) CMB power spectrum is in good agreement with the published WMAP5 results. Residual monopoles and dipoles were found to be small (≾3 μK) or negligible in the five-year data. We comprehensively tested the assumptions that were made about the foregrounds (e.g., dust spectral index, power-law spectral index prior, templates), and found that the CMB power spectrum was insensitive to these choices. We confirm the asymmetry of power between the north and south ecliptic hemispheres, which appears to be robust against foreground modeling. The map of low-frequency spectral indices indicates a steeper spectrum on average (β = –2.97 ± 0.21) relative to those found at low (~GHz) frequencies.

Item Type:Article
Related URLs:
Dickinson, C.0000-0002-0045-442X
Additional Information:© 2009 The American Astronomical Society. Received 2009 March 24; accepted 2009 August 13; published 2009 October 26. We acknowledge the use of the HEALPix software (Gorski et al. 2005) and analysis package for deriving the results in this paper. We acknowledge the 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. We acknowledge the use of the NOTUR super-computing facilities, the IPAC Planck cluster, and the Titan cluster owned and maintained by the University of Oslo. C.D. acknowledges support from the U.S. Planck project, which is funded by the NASA Science Mission Directorate. The work of C.D. was also supported in part by a STFC Advanced Fellowship. H.K.E. acknowledges financial support from the Research Council of Norway. B.D.W. was partially supported by NSF-AST 0507676 and NASA JPL 1236748.
Funding AgencyGrant Number
U.S. Planck projectUNSPECIFIED
Research Council of NorwayUNSPECIFIED
NSFAST 0507676
Science & Technology Facilities Council (STFC) Advanced FellowshipUNSPECIFIED
Subject Keywords:cosmic microwave background; cosmology: observations; radio continuum: ISM
Issue or Number:2
Record Number:CaltechAUTHORS:20091111-111712637
Persistent URL:
Official Citation:Bayesian Component Separation and Cosmic Microwave Background Estimation for the Five-Year WMAP Temperature Data C. Dickinson, H. K. Eriksen, A. J. Banday, J. B. Jewell, K. M. Górski, G. Huey, C. R. Lawrence, I. J. O'Dwyer, and B. D. Wandelt 2009 ApJ 705 1607-1623 doi: 10.1088/0004-637X/705/2/1607
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16666
Deposited By: Tony Diaz
Deposited On:16 Nov 2009 21:49
Last Modified:09 Mar 2020 13:18

Repository Staff Only: item control page