(ORDO NEWS) — Scientists have mapped one of the “bones” of the Milky Way galaxy for the first time.
This bone is a long dense filament of cold gas in the densest part of one of the galaxy’s spiral arms. Its length is about 195 light years: The map from the Stratospheric Observatory for Infrared Astronomy (SOFIA) aircraft gives us the first complete picture of its magnetic fields.
The result does not live up to expectations. The magnetic fields are not aligned along the length of the bone, but are more chaotic, and the average magnetic field is neither parallel nor perpendicular to the bone. According to the researchers, this could help us better understand not only the structure of spiral galaxies, but also their star formation.
Scientists first identified one of the Milky Way’s bones back in 2013; they have since found a total of 18 such galactic bones. Our galaxy currently has a fairly low star formation rate, around three solar masses per year; however, what star formation does take place usually takes place in these so-called bones.
Just as your bones are the densest part of your arms, galactic bones are the densest part of the Milky Way. The defining properties of these bones are that they must be at least 50 times as long as they are wide, as well as close and mostly parallel to the galactic plane.
Astronomers have also taken careful measurements of their size, mass, temperature, height, and density.
Research has shown that magnetic fields are sometimes, but often, not perpendicular to the center of the bone. Those regions with perpendicular magnetic fields tend to be the densest regions—with the most active star formation.
In other regions, the magnetic fields are either parallel or randomly aligned. In these areas, the magnetic field seems to be strongest against the gravitational collapse of the bones; The researchers said star forming regions are the weakest against gravitational collapse.
This suggests that magnetic fields play a role in preventing G47 bone destruction and bone formation in areas of higher density. However, magnetic fields in lower density regions are complex and confusing, and the role played by the magnetic field is not clear.
Since G47 was only the first in a series of in-depth studies of the magnetic fields of galactic bones, the remaining work may help resolve this mystery. The first glance, of course, intrigued.
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