One of The Milky Way's 'Bones' Was Just Fully Mapped For The First Time

Scientists have mapped one of the bones of the Milky Way galaxy for the first time.

The densest part of the spiral arms is the bone. It measures around 195 light-years in length and gives us the first complete picture of the magnetic fields.

The result is different than expected. The magnetic fields are not aligned along the length of the bone, but are more higgledy-piggledy. The researchers said that this can help us understand the star formation of spiral galaxies.

It was difficult to image magnetic fields at high resolution over the entire bones before SOFIA.

We are able to get so many independent measurements of the magnetic field direction across these bones, allowing us to really dive into the importance of the magnetic field in these massive filamentary clouds.

The bones of the Milky Way were first identified by scientists in 2013; since then, 18 of them have been found. Our galaxy has a low rate of star formation, around three solar mass per year, but what star formation does happen tends to happen in these bones.

The densest part of the Milky Way's arms are the bones. The bones must be at least 50 times longer than they are wide and be close to the galactic plane to be considered a defining property.

Astronomers have measured their size, mass, temperature, altitude, and density.

The magnetic fields of the bones have been poorly constrained. SOFIA, a modified Boeing that flies above Earth's stratosphere, was used by the team to take 10 bones. The first one is G47.

The rate at which stars form in a cloud can be set by magnetic fields. They can guide the flow of gas, shape the bones, and affect the quantity and size of the densest pockets of gas that will eventually collapse to form stars.

By mapping the orientation of the fields, we can estimate the relative importance of the magnetic field to that of gravity.

The team used SOFIA to take pictures of the dust in G47. The direction of the magnetic field can be detected by the direction in which the dust grains align. Magnetic field lines can be mapped using that polarization.

The study showed that the magnetic fields can be found at the center of the bone. The densest regions with the most active star formation are the ones with the most magnetic fields.

The magnetic fields can be parallel or randomly aligned. The regions with the strongest magnetic field are the ones with the weakest star formation regions.

Magnetic fields may be involved in keeping the G47 bone from collapsing and in shaping the bone in the higher density regions. The magnetic fields in the lower density regions are complicated and messy.

Since G47 was the first in a series of in-depth studies of the magnetic fields of galactic bones, the remaining work may help resolve the mystery. The first look has been intriguing.

The research was published in a journal.