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Separation of anomalous and synchrotron emissions using WMAP polarization data
Miville-Deschenes M.-A., Ysard N., Lavabre A., Ponthieu N., Macias-Perez J.F. et al
Astronomy and Astrophysics 490 (2008) 1093-1102 - http://hal.in2p3.fr/in2p3-00258736
Physique/Astrophysique/Cosmologie et astrophysique extra-galactique
Planète et Univers/Astrophysique
Separation of anomalous and synchrotron emissions using WMAP polarization data
M.-A. Miville-Deschenes1, N. Ysard1, A. Lavabre1, N. Ponthieu1, J.F. Macias-Perez2, J. Aumont2, 3, J.P. Bernard3
1 :  IAS - Institut d'astrophysique spatiale
CNRS : UMR8617 – INSU – Université Paris XI - Paris Sud
bat. 121 91405 ORSAY CEDEX
2 :  LPSC - Laboratoire de Physique Subatomique et de Cosmologie
CNRS : UMR5821 – IN2P3 – Université Joseph Fourier - Grenoble I – Institut Polytechnique de Grenoble - Grenoble Institute of Technology
53 avenue des Martyrs - 38026 Grenoble Cedex
3 :  CESR - Centre d'étude spatiale des rayonnements
CNRS : UMR5187 – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier (UPS) - Toulouse III
9 Av du colonel Roche - BP 4346 31028 TOULOUSE CEDEX 4
The main goals of this study is to use the information from both WMAP intensity and polarization data to do a separation of the Galactic components, with a focus on the synchrotron and anomalous emissions. Our analysis is made at 23 GHz where the signal-to-noise ratio is the highest and the estimate of the CMB map is less critical. Our estimate of the synchrotron intensity is based on an extrapolation of the Haslam 408 MHz data with a spatially varying spectral index constrained by the WMAP 23 GHz polarization data and a bi-symmetrical spiral model of the galactic magnetic field with a turbulent part following a -5/3 power law spectrum. The 23 GHz polarization data are found to be compatible with a magnetic field with a pitch angle p=-8.5 degrees and an amplitude of the turbulent part of the magnetic field 0.57 times the local value of the field, in agreement with what is found using rotation measures of pulsars and polarized extinction by dust. The synchrotron spectral index between 408 MHz and 23 GHz obtained from polarization data and our model of the magnetic field has a mean value of Beta=-3.00 with a limited spatial variation with a standard deviation of 0.06. When thermal dust, free-free and synchrotron are removed from the WMAP intensity data, the residual anomalous emission is highly correlated with thermal dust emission with a spectrum in agreement with spinning dust models. Considering a classical model of the large scale Galactic magnetic field, we show that the polarization data of WMAP are in favor of a soft synchrotron intensity highly correlated with the 408 MHz data. Furthermore the combination of the WMAP polarization and intensity data brings strong evidence for the presence of unpolarized spinning dust emission in the 20-60 GHz range.

Articles dans des revues avec comité de lecture
Astronomy and Astrophysics (Astron. Astrophys.)
Publisher EDP Sciences
ISSN 0004-6361 (eISSN : 1432-0756)

LPSC 0821
accepted by A and A
Polarization – radiation mechanisms – non-thermal – turbulence – magnetic fields – dust
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