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Component separation methods for the PLANCK mission

Leach, S. M. and Cardoso, J.-F. and Baccigalupi, C. and Barreiro, R. B. and Betoule, M. and Bobin, J. and Bonaldi, A. and Delabrouille, J. and de Zotti, G. and Dickinson, C. and Eriksen, H. K. and González-Nuevo, J. and Hansen, F. K. and Herranz, D. and Le Jeune, M. and López-Caniego, M. and Martínez-González, E. and Massardi, M. and Melin, J.-B. and Miville-Deschênes, M.-A. and Patanchon, G. and Prunet, S. and Ricciardi, S. and Salerno, E. and Sanz, J. L. and Starck, J.-L. and Stivoli, F. and Stolyarov, V. and Stompor, R. and Vielva, P. (2008) Component separation methods for the PLANCK mission. Astronomy and Astrophysics, 491 (2). pp. 597-615. ISSN 0004-6361.

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Context. The PLANCK satellite will map the full sky at nine frequencies from 30 to 857 GHz. The CMB intensity and polarization that are its prime targets are contaminated by foreground emission. Aims. The goal of this paper is to compare proposed methods for separating CMB from foregrounds based on their different spectral and spatial characteristics, and to separate the foregrounds into “components” with different physical origins (Galactic synchrotron, free-free and dust emissions; extra-galactic and far-IR point sources; Sunyaev-Zeldovich effect, etc.) Methods. A component separation challenge has been organised, based on a set of realistically complex simulations of sky emission. Several methods including those based on internal template subtraction, maximum entropy method, parametric method, spatial and harmonic cross correlation methods, and independent component analysis have been tested. Results. Different methods proved to be effective in cleaning the CMB maps of foreground contamination, in reconstructing maps of diffuse Galactic emissions, and in detecting point sources and thermal Sunyaev-Zeldovich signals. The power spectrum of the residuals is, on the largest scales, four orders of magnitude lower than the input Galaxy power spectrum at the foreground minimum. The CMB power spectrum was accurately recovered up to the sixth acoustic peak. The point source detection limit reaches 100 mJy, and about 2300 clusters are detected via the thermal SZ effect on two thirds of the sky. We have found that no single method performs best for all scientific objectives. Conclusions. We foresee that the final component separation pipeline for PLANCK will involve a combination of methods and iterations between processing steps targeted at different objectives such as diffuse component separation, spectral estimation, and compact source extraction.

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de Zotti, G.0000-0003-2868-2595
Additional Information:© ESO 2008. Received 2 May 2008 / Accepted 17 September 2008. The work reported in this paper was carried out by Working Group 2 of the PLANCK Collaboration. PLANCK is a mission of the European Space Agency. The Italian group were supported in part by ASI (contract Planck LFI Phase E2 Activity). The US PLANCK Project is supported by the NASA Science Mission Directorate. The ADAMIS team at APC has been partly supported by the Astro-Map and Cosmostat ACI grants of the French ministry of research, for the development of innovative CMB data analysis methods. The IFCA team acknowledges partial financial support from the Spanish project AYA2007- 68058-C03-02. This research used resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the US Department of Energy under Contract No. DE-AC02-05CH11231. D.H., J.L.S. and E.S. would like to acknowledge partial financial support from joint CNR-CSIC research project 2006-IT-0037. R.S. acknowledges support of the E.C. Marie Curie IR Grant (mirg-ct-2006-036614). C.B. was partly supported by the NASA LTSA Grant NNG04CG90G. S.M.L. would like to thank the kind hospitality of the APC, Paris for a research visit where part of this work was completed. We thank Carlo Burigana for a careful reading of the manuscript. We acknowledge the use of the Legacy Archive for Microwave Background Data Analysis (LAMBDA). Support for LAMBDA is provided by the NASA Office of Space Science. The results in this paper have been derived using the HEALPix package (Górski et al. 2005).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NASA Science Mission DirectorateUNSPECIFIED
Astro-Map and Cosmostat ACI grants of the French ministry of researchUNSPECIFIED
Spanish projectAYA2007- 68058-C03-02
Department of Energy (DOE)DE-AC02-05CH11231
E.C. Marie Curie IR Grantmirg-ct-2006-036614
Subject Keywords:cosmology: cosmic microwave background; methods: data analysis
Record Number:CaltechAUTHORS:20090526-094724857
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:14296
Deposited By: Tony Diaz
Deposited On:25 Jun 2009 20:34
Last Modified:24 Oct 2017 22:21

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