If correct, the theory could explain the appearance in the sky of two rope-like structures in the Milky Way whose origins are currently uncertain.
The North Polar Spur (NPS), described by NASA as “the most spectacular coherent structure in the soft X-ray sky,” and the Fan Region are two of the brightest radio-emitting gas structures seen in the night sky.
“Astronomers have long been puzzled by what these structures are,” Dunlap Institute Research Associate, Dr. Jennifer West, told Vice. “If our eyes could see radio light they would fill most of the sky.”
West is one of the authors of a pre-print paper accepted for publication in The Astrophysical Journal. The paper presents a simple model that can explain not just the NPS and the Fan Region, but also several other prominent filamentary loops of radio wave-emitting dust.
Estimates of the size of the NPS range from hundreds to thousands of light years in length, as it’s still difficult for astronomers to assess just how far away from Earth this structure is. Yet, it is still one of the largest structures in the Milky Way.
Despite its tremendous size, the NPS shines brightly in the radio and X-ray regions of the electromagnetic spectrum but not in the region of visible light, and this means it is invisible to the naked eye.
Both the NPS and the Fan Regions were first observed as radio astronomy began to boom in the 1960s, discovered in 1958 and 1964 respectively.
They have been widely studied in the six decades since their discovery, but this new research differs from previous thinking as it treats both as part of the same structure.
This new treatment of these structures could explain why the NPS has been difficult to pinpoint, with the upper regions of the structure appearing to be closer to the Earth, with the lower portions of it appearing more distant.
An image of the North Polar Spur at high resolution in the ROSAT/PSPC survey. Recent research indicates that this filamentary structure of gas could be part of a highly magnetized structure through which the solar system is travelling.
The research corresponds with previous studies that have suggested the NPS is highly magnetized, and other observational studies of these radio bright structures.
The authors suggest that these cosmic ropes of gas are long, magnetized, and parallel filamentary structures that surround the Local Bubble of the Milky Way in which the Sun is embedded like a tunnel.
The authors believe this new suggestion could help explain the increasingly common discovery of radio-bright rope-like structures and could give us a better handle on magnetism in the wider Milky Way.
“Understanding the contributions of this local emission is critical to developing a complete model of the Galactic magnetic field,” they write in the paper.
“These very nearby structures also provide context to help understand similar non-thermal, filamentary structures that are increasingly being observed with modern radio telescopes.”
West told Vice that this new unified approach to tackling the mysteries of filamentary structures in the Milky Way required her to look at our galaxy from a new angle, both figuratively and literally.
**By Robert Lea