Turbulent origin of the galactic center magnetic field: Nonthermal radio filaments

A great deal of study has been conducted over the last 20 years on the origin of the magnetic activity in the Galactic center. One of the most popular hypotheses assumes a milligauss magnetic field with poloidal geometry, pervading the inner few hundred parsecs of the Galactic center region. However, there is growing observational evidence for the large-scale distribution of a much weaker field of B ≲ 10 μG in this region. Here we propose that the Galactic center magnetic field originates from turbulent activity, which is known to be extreme in the central hundred parsecs. In this picture, the spatial distribution of the magnetic field energy is highly intermittent, and the regions of strong field have filamentary structure. We propose that the observed nonthermal radio filaments appear in (or, possibly, may be identified with) such strongly magnetized regions. At the same time, the large-scale diffuse magnetic field is weak. Both results of our model can explain the magnetic field measurements of the Galactic center region. In addition, we discuss the role of ionized outflow from stellar clusters in producing the long magnetized filaments perpendicular to the Galactic plane.