Dust polarization modeling at large-scale over the Northern Galactic cap
  using EBHIS and Planck data
  The primary source of systematic uncertainty in the quest for the B-mode
polarization of the Cosmic Microwave Background (CMB) introduced by primordial
gravitational waves is polarized thermal emission from Galactic dust.
Therefore, accurate characterization and separation of the polarized thermal
dust emission is an essential step in distinguishing such a faint CMB B-mode
signal. We provide a modelling framework to simulate polarized thermal dust
emission based on the model described in Ghosh et al. (2017), making use of
both the Planck dust and Effelsberg-Bonn HI surveys over the northern Galactic
cap. Our seven-parameter dust model, incorporating both HI gas in three
different column density templates as a proxy for spatially variable dust
intensity and a phenomenological model of Galactic magnetic field, is able to
reproduce both 1- and 2-point statistics of the observed dust polarization maps
seen by Planck at 353 GHz over a selected low-column density region in the
northern Galactic cap. This work has important applications in assessing the
accuracy of component separation methods and in quantifying the confidence
level of separating polarized Galactic emission and the CMB B-mode signal, as
is needed for ongoing and future CMB missions.
