A Unified Model for the Fan Region and the North Polar Spur: A bundle of filaments in the Local Galaxy

Abstract

We present a simple, unified model that can explain two of the brightest, large-scale, diffuse, polarized radio features in the sky, the North Polar Spur (NPS) and the Fan Region, along with several other prominent loops. We suggest that they are long, magnetized, and parallel filamentary structures that surround the Local arm and/or Local Bubble, in which the Sun is embedded. We show this model is consistent with the large number of observational studies on these regions, and is able to resolve an apparent contradiction in the literature that suggests the high latitude portion of the NPS is nearby, while lower latitude portions are more distant. Understanding the contributions of this local emission is critical to developing a complete model of the Galactic magnetic field. These very nearby structures also provide context to help understand similar non-thermal, filamentary structures that are increasingly being observed with modern radio telescopes.

21 pages, 13 figures, Accepted to ApJ

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Cited by in corpus (11)

• The Coherent Magnetic Field of the Milky Way
• Mysterious Odd Radio Circle near the Large Magellanic Cloud -- An Intergalactic Supernova Remnant?
• Rotation measure structure functions with higher-order stencils as a probe of small-scale magnetic fluctuations and its application to the Small and Large Magellanic Clouds
• The coherent magnetic field of the Milky Way halo, Local Bubble and Fan Region
• Polarized Synchrotron Foreground Assessment for CMB Experiments
• Neutral hydrogen filaments in interstellar media: Are they physical?
• Morphological Evidence for the eROSITA Bubbles Being Giant and Distant Structures
• The magnetic field of the Radcliffe Wave: starlight polarization at nearest approach to the Sun
• Discovery of a filamentary synchrotron structure connected to the coherent magnetic field in the outer Galaxy
• Superposing the Magnetic spiral structure of the Milky Way, on the stellar spiral arms -- Matching the unique galactic magnetic field reversal Zone with two galactic spiral arm Segments
• Interaction Between Rogue HI Clouds and the Magnetic Field High Above the Galaxy