Modeling the magnetized Local Bubble from dust data
  The Sun is embedded in the so-called Local Bubble (LB) -- a cavity of hot
plasma created by supernova explosions and surrounded by a shell of cold, dusty
gas. Knowing the local distortion of the Galactic magnetic field associated
with the LB is critical for the modeling of interstellar polarization data at
high Galactic latitudes. In this his paper, we relate the structure of the
Galactic magnetic field on the LB scale to three-dimensional (3D) maps of the
local interstellar medium (ISM). First, we extracted the geometry of the LB
shell, its inner surface, in particular from 3D dust extinction maps of the
local ISM. We expanded the shell inner surface in spherical harmonics, up to a
variable maximum multipole degree, which enabled us to control the level of
complexity for the modeled surface. Next, we applied an analytical model for
the ordered magnetic field in the shell to the modeled shell surface. This
magnetic field model was successfully fitted to the \textit{Planck} 353~GHz
dust polarized emission maps over the Galactic polar caps. For each polar cap,
the direction of the mean magnetic field derived from dust polarization
(together with the prior that the field points toward longitude $90^\circ \pm
90^\circ$) is found to be consistent with the Faraday spectra of the nearby
diffuse synchrotron emission. Our work presents a new approach to modeling the
local structure of the Galactic magnetic field. We expect our methodology and
our results to be useful both in modeling the local ISM as traced by its
different components and in modeling the dust polarized emission, which is a
long-awaited input for studies of the polarized foregrounds for cosmic
microwave background.
