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Statistical simulations of the dust foreground to cosmic microwave background polarization

Vansyngel, F. and Boulanger, F. and Ghosh, T. and Wandelt, B. and Aumont, J. and Bracco, A. and Levrier, F. and Martin, P. G. and Montier, L. (2017) Statistical simulations of the dust foreground to cosmic microwave background polarization. Astronomy and Astrophysics, 603 . Art. No. A62. ISSN 0004-6361.

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The characterization of the dust polarization foreground to the cosmic microwave background (CMB) is a necessary step toward the detection of the B-mode signal associated with primordial gravitational waves. We present a method to simulate maps of polarized dust emission on the sphere that is similar to the approach used for CMB anisotropies. This method builds on the understanding of Galactic polarization stemming from the analysis of Planck data. It relates the dust polarization sky to the structure of the Galactic magnetic field and its coupling with interstellar matter and turbulence. The Galactic magnetic field is modeled as a superposition of a mean uniform field and a Gaussian random (turbulent) component with a power-law power spectrum of exponent αM. The integration along the line of sight carried out to compute Stokes maps is approximated by a sum over a small number of emitting layers with different realizations of the random component of the magnetic field. The model parameters are constrained to fit the power spectra of dust polarization EE, BB, and TE measured using Planck data. We find that the slopes of the E and B power spectra of dust polarization are matched for α_M = −2.5, an exponent close to that measured for total dust intensity but larger than the Kolmogorov exponent − 11/3. The model allows us to compute multiple realizations of the Stokes Q and U maps for different realizations of the random component of the magnetic field, and to quantify the variance of dust polarization spectra for any given sky area outside of the Galactic plane. The simulations reproduce the scaling relation between the dust polarization power and the mean total dust intensity including the observed dispersion around the mean relation. We also propose a method to carry out multifrequency simulations, including the decorrelation measured recently by Planck, using a given covariance matrix of the polarization maps. These simulations are well suited to optimize component separation methods and to quantify the confidence with which the dust and CMB B-modes can be separated in present and future experiments. We also provide an astrophysical perspective on our phenomenological modeling of the dust polarization spectra.

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Alternate Title:Statistical simulations of the dust foreground to CMB polarization
Additional Information:© 2017 ESO. Article published by EDP Sciences. Received 1 November 2016; Accepted 24 March 2017; Published online 10 July 2017. Planck ( is a project of the European Space Agency (ESA) with instruments provided by two scientific consortia funded by ESA member states and led by Principal Investigators from France and Italy, telescope reflectors provided through a collaboration between ESA and a scientific consortium led and funded by Denmark, and additional contributions from NASA (USA). The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement No. 267934.
Funding AgencyGrant Number
European Research Council (ERC)267934
Subject Keywords:polarization – ISM: general – cosmic background radiation – submillimeter: ISM
Record Number:CaltechAUTHORS:20170901-083101483
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Official Citation:Statistical simulations of the dust foreground to cosmic microwave background polarization F. Vansyngel, F. Boulanger, T. Ghosh, B. Wandelt, J. Aumont, A. Bracco, F. Levrier, P. G. Martin and L. Montier A&A, 603 (2017) A62 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:81058
Deposited By: Tony Diaz
Deposited On:01 Sep 2017 17:14
Last Modified:03 Oct 2019 18:38

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