Issue |
A&A
Volume 652, August 2021
|
|
---|---|---|
Article Number | A130 | |
Number of page(s) | 31 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361/201833962 | |
Published online | 23 August 2021 |
Galactic magnetic field reconstruction using the polarized diffuse Galactic emission: formalism and application to Planck data
1
Univ. Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3,
38000
Grenoble,
France
e-mail: pelgrims@physics.uoc.gr
2
Institute of Astrophysics, Foundation for Research and Technology-Hellas,
Vasilika Vouton,
70013
Heraklion,
Greece
3
Department of Physics, and Institute for Theoretical and Computational Physics, University of Crete,
70013
Heraklion,
Greece
4
Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology,
Cambridge,
MA
02139,
USA
Received:
26
July
2018
Accepted:
11
May
2021
The polarized Galactic synchrotron and thermal dust emission constitutes a major tool in the study of the Galactic magnetic field (GMF) and in constraining its strength and geometry for the regular and turbulent components. In this paper, we review the modeling of these two components of the polarized Galactic emission and present our strategy for optimally exploiting the currently existing data sets. We investigate a Markov chain Monte Carlo (MCMC) method to constrain the model parameter space through maximum-likelihood analysis, focusing mainly on dust polarized emission. Relying on simulations, we demonstrate that our methodology can be used to constrain the regular GMF geometry. Fitting for the reduced Stokes parameters, this reconstruction is only marginally dependent of the accuracy of the reconstruction of the Galactic dust grain density distribution. However, the reconstruction degrades, apart from the pitch angle, when including a turbulent component on the order of the regular one as suggested by current observational constraints. Finally, we applied this methodology to a set of Planck polarization maps at 353 GHz to obtain the first MCMC based constrains on the large-scale regular-component of the GMF from the polarized diffuse Galactic thermal dust emission. By testing various models of the dust density distribution and of the GMF geometry, we prove that it is possible to infer the large-scale geometrical properties of the GMF. We obtain coherent three-dimensional views of the GMF, from which we infer a mean pitch angle of 27 degrees with 14% scatter, which is in agreement with results obtained in the literature from synchrotron emission.
Key words: polarization / dust, extinction / submillimeter: ISM / ISM: magnetic fields / methods: statistical / cosmic background radiation
© V. Pelgrims et al. 2021
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.