Modelling the Polarisation of Microwave Foreground Emission on Large Angular Scales

TL;DR

This paper models the large-scale polarised microwave foreground emission from the Galaxy by simulating the Galactic Magnetic Field, providing templates useful for CMB experiments and future magnetic field studies.

Contribution

It extends previous models by including polarised synchrotron radiation based solely on the GMF, offering independent predictions for large-scale polarisation signals.

Findings

Generated templates of polarised foregrounds for CMB frequencies.

Provides a method to constrain the Galactic Magnetic Field with future data.

Offers tools for forecasting experimental sensitivity to CMB polarisation.

Abstract

Templates for polarised emission from Galactic foregrounds at frequencies relevant to Cosmic Microwave Background (CMB) polarisation experiments are obtained by modelling the Galactic Magnetic Field (GMF) on large scales. This work extends the results of O'Dea et al. by including polarised synchrotron radiation as a source of foreground emission. The polarisation direction and fraction in this calculation are based solely on the underlying choice of GMF model and therefore provide an independent prediction for the polarisation signal on large scales. Templates of polarised foregrounds may be of use when forecasting effective experimental sensitivity. In turn, as measurements of the CMB polarisation over large fractions of the sky become routine, this model will allow for the data to constrain parameters in the, as yet, not well understood form of the GMF.