Multi-scale Magnetic Fields in the Central Molecular Zone: Inference
  from the Gradient Technique
  The central molecular zone (CMZ) plays an essential role in regulating the
nuclear ecosystem of our Galaxy. To get an insight into the magnetic fields of
the CMZ, we employ the Gradient Technique (GT), which is rooted in the
anisotropy of magnetohydrodynamic turbulence. Our analysis is based on the data
of multiple wavelengths, including molecular emission lines, radio 1.4 GHz
continuum image, and Herschel 70 $\mu$m image, as well as ionized [Ne II] and
Paschen-alpha emissions. The results are compared with the observations of
Planck 353 GHz and High-resolution Airborne Wideband Camera Plus (HWAC+) 53
$\mu$m polarized dust emissions. We map the orientation of the magnetic field
at multiple wavelengths across the central molecular zone, including close-ups
of the Radio Arc and Sagittarius A West regions, on multi scales from $\sim$
0.1 pc to 10 pc. The magnetic fields towards the central molecular zone traced
by GT are globally compatible with the polarization measurements, accounting
for the contribution from the galactic foreground and background. This
correspondence suggests that the magnetic field and turbulence are dynamically
crucial in the galactic center. We find that the magnetic fields associated
with the Arched filaments and the thermal components of the Radio Arc are in
good agreement with the HAWC+ polarization. Our measurement towards the
non-thermal Radio Arc reveals the poloidal magnetic field components in the
galactic center. For Sagittarius A West region, we find a great agreement
between the GT measurement using [Ne II] emission and HWAC+ 53 $\mu$m
observation. We use GT to predict the magnetic fields associated with ionized
Paschen-alpha gas down to scales of 0.1 pc.
