Planck intermediate results. XLIV. The structure of the Galactic magnetic field from dust polarization maps of the southern Galactic cap

Understand

We study the statistical properties of interstellar dust polarization at high Galactic latitude, using the Stokes parameter Planck maps at 353 GHz.

• Our aim is to advance the understanding of the magnetized interstellar medium (ISM), and to provide a model of the polarized dust foreground for cosmic microwave background component-separation procedures.
• Focusing on the southern Galactic cap, we examine the statistical distributions of the polarization fraction ($p$) and angle ($\psi$) to characterize the ordered and turbulent components of the Galactic magnetic field (GMF) in the solar neighbourhood.
• We relate patterns at large angular scales in polarization to the orientation of the mean (ordered) GMF towards Galactic coordinates $(l_0,b_0)=(70^\circ \pm 5^\circ,24^\circ \pm 5^\circ)$.