The Milky Way’s rotating disk of gas and dust gives rise to the graceful spiral arms that make up the galaxy’s most active star-forming sites. Researchers now using airborne telescopes high above the Earth’s atmosphere have discovered the mechanism of how magnetic fields shape star birth in the dense filaments, or “bones”, that thread through these arms. I found
A new study shows that a galactic-scale magnetic field pumps matter from one region to another based on its orientation and strength, preventing the dust and gas that make up the densest regions from collapsing under gravity. It explains how. These processes weaken star formation. Without them, we would have had a much brighter night sky than we do today.
Ground-based telescope observations in 2015 confirmed the physical properties of the bones of gas and dust that cover the arms of the Milky Way galaxy. However, researchers were unaware of the exact role of magnetic fields in small-scale star-forming activity. “We knew bone existed, but at the time we didn’t have a way to map the details of its magnetic structure,” says Simon Coudé, a postdoctoral researcher at Worcester State University and the Center for Astrophysics. . Harvard & Smithsonian. Coudé announced the new findings at his 2023 Winter Meeting of the American Astronomical Society.
For this work, researchers determine the fine-scale orientation of these magnetic fields by measuring how dust particles align. Specifically, we are quantifying how magnetic properties prevent the gas and dust contained in giant bones from collapsing and forming stars. Using data from instruments onboard the Boeing 747 telescope SOFIA, in the last year of activity, “we were able to see the structure of the star-forming cloud field over large swaths of the galaxy.” He says Coudé.
One bone map from this project showed that the magnetic field tends to be perpendicular to the length of the bone in dense regions of active star birth, and more parallel elsewhere. This could mean that a parallel field from a less dense region pumps material into a denser region, where, despite the addition of star-forming material, the field continues to gravitationally collapse. The researchers say it is strong enough to limit They also found that magnetic fields along other galactic bones are strong enough to dampen star formation in all but the most active regions.
“We know that magnetic fields permeate the entire galaxy,” said Enrique López Rodríguez, an extragalactic astronomer at the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University. Ultimately, he says, it will lead to understanding how the balance between gravity and large-scale magnetic fields determines star formation at the smallest scales in other galaxies and our own. adds.
