Turbulent Origin of the Galactic-Center Magnetic Field: Nonthermal Radio Filaments

Abstract

A great deal of study has been carried out over the last twenty years on the origin of the magnetic activity in the Galactic center. One of the most popular hypotheses assumes milli-Gauss magnetic field with poloidal geometry, pervading the inner few hundred parsecs of the Galactic-center region. However, there is a growing observational evidence for the large-scale distribution of a much weaker field of B \lesssim 10 micro G in this region. Here, we propose that the Galactic-center magnetic field originates from turbulent activity that 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 structures. 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 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.

11 pages, accepted to ApJ Letters

References in corpus (5)

• Hot and Diffuse Clouds near the Galactic Center Probed by Metastable H3+
• A $\lambda$20cm Survey of the Galactic Center Region I: Detection of Numerous Linear Filaments
• Evidence for a Weak Galactic Center Magnetic Field from Diffuse Low Frequency Nonthermal Radio Emission
• High-Resolution, Wide-Field Imaging of the Galactic Center Region at 330 MHz
• The Nature of Nonthermal X-ray Filaments Near the Galactic Center

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