New Constraints on the Global Structure of the Coherent Galactic Magnetic Field

We present a major revision of the widely used model of the coherent
magnetic field of the Galaxy from Jannson&Farrar (JF12). For this
purpose, we use new full-sky data of extragalactic rotation measures,
final polarized intensity maps from WMAP and Planck and the rotation
measures of Galactic pulsars. Furthermore, we tune auxiliary models
for the thermal electron density to the dispersion measures of
Galactic pulsars and employ a suite of state-of-the-art cosmic-ray
electrons models to predict the synchrotron emission from the
Galaxy. Finally, we developed new divergence-free parametric models of
the global structure of the magnetic field and tune them to the data.

We will discuss the deflection of ultrahigh-energy cosmic rays implied
by this new model and estimate a lower limit on their uncertainties
from a variation of model assumptions.