SOFIA observes Galactic Superwind in Messier 82
Astronomers using NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) have discovered that the galactic wind flowing from the center of Messier 82 is aligned along a magnetic field and transports a very large mass of gas and dust — approximately 50-60 million solar masses.
This composite image shows the starburst galaxy Messier 82. The magnetic field detected by SOFIA, shown as streamlines, appears to follow the bipolar outflows (red) generated by the intense nuclear starburst. The image combines visible starlight (gray) and a tracing of hydrogen gas (red) from the Kitt Peak Observatory, with near-infrared and mid-infrared starlight and dust (yellow) from SOFIA and NASA’s Spitzer Space Telescope.
This composite image shows the starburst galaxy Messier 82. The magnetic field detected by SOFIA, shown as streamlines, appears to follow the bipolar outflows (red) generated by the intense nuclear starburst. The image combines visible starlight (gray) and a tracing of hydrogen gas (red) from the Kitt Peak
Messier 82 is an edge-on starburst galaxy located about 12 million light-years away. It appears high in the northern spring sky in the direction of the constellation Ursa Major.
First discovered by the German astronomer Johann Elert Bode in 1774, it is also called the Cigar Galaxy because of the elongated elliptical shape produced by the tilt of its starry disk relative to our line of sight.
Messier 82 is famous for its extraordinary speed in making new stars, with stars being born 10 times faster than in our Milky Way Galaxy.
“The space between galaxies is not empty. It contains gas and dust — which are the seed materials for stars and galaxies,” said co-author Dr. Enrique Lopez-Rodriguez, a Universities Space Research Association scientist working on the SOFIA team.
“Now, we have a better understanding of how this matter escaped from inside galaxies over time.”
Besides being a classic example of a starburst galaxy, Messier 82 also has strong winds blowing gas and dust into intergalactic space.
Astronomers have long theorized that these winds would also drag the galaxy’s magnetic field in the same direction, but despite numerous studies, there has been no observational proof of the concept.
Dr. Lopez-Rodriguez and colleagues found definitively that the wind from Messier 82 not only transports a huge amount of gas and dust into the intergalactic medium, but also drags the magnetic field so it is perpendicular to the galactic disk.
In fact, the wind drags the magnetic field more than 2,000 light-years across — close to the width of the wind itself.
“One of the main objectives of this research was to evaluate how efficiently the galactic wind can drag along the magnetic field,” Dr. Lopez-Rodriguez said.
“We did not expect to find the magnetic field to be aligned with the wind over such a large area.”
The SOFIA observations indicate that the powerful winds associated with the starburst phenomenon could be one of the mechanisms responsible for seeding material and injecting a magnetic field into the nearby intergalactic medium.
If similar processes took place in the early Universe, they would have affected the fundamental evolution of the first galaxies.
“Studying intergalactic magnetic fields — and learning how they evolve — is key to understanding how galaxies evolved over the history of the Universe,” said University of Minnesota’s Professor Terry Jones, lead author of the study.