Model of the polarized foreground diffuse Galactic emissions from 33 to 353 GHz

TL;DR

This paper develops 3D models of the polarized Galactic emissions from synchrotron and dust, fitting them to WMAP and Archeops data to improve foreground estimates for CMB studies.

Contribution

It introduces a comprehensive 3D modeling approach of Galactic polarized emissions, fitting parameters to observational data to better understand foreground contamination.

Findings

Best-fit models suggest negligible isotropic turbulent magnetic field at large scales.

Models are consistent across multiple frequency bands from 33 to 353 GHz.

The results aid in foreground estimation for CMB polarization experiments.

Abstract

We present 3D models of the Galactic magnetic field including regular and turbulent components, and of the distribution of matter in the Galaxy including relativistic electrons and dust grains. By integrating along the line of sight, we construct maps of the polarized Galactic synchrotron and thermal dust emissions for each of these models. We perform a likelihood analysis to compare the maps of the Ka, Q, V and W bands of the Wilkinson Microwave Anisotropy Probe (Wmap) and the 353 GHz Archeops data to the models obtained by varying the pitch angle of the regular magnetic field, the relative amplitude of the turbulent magnetic field and the extrapolation spectral indices of the synchrotron and thermal dust emissions. The best-fit parameters obtained for the different frequency bands are very similar and globally the data seem to favor a negligible isotropic turbulent magnetic field component at large angular scales (an anisotropic line-of-sight ordered component can not be studied using these data). From this study, we conclude that we are able to propose a consistent model of the polarized diffuse Galac- tic synchrotron and thermal dust emissions in the frequency range from 33 to 353 GHz, where most of the CMB studies are performed and where we expect a mixture of these two main foreground emissions. This model can be very helpful to estimate the contamination by foregrounds of the polarized CMB anisotropies, for experiments like the Planck satellite.