From NASA
January 14, 2021
Magnetic fields in Messier 82 or the Cigar Galaxy are represented as lines over a composite image of visible light and infrared of the galaxy from the Hubble Space Telescope and the Spitzer Space Telescope. Star winds streaming from hot new stars form a galactic superwind that ejects hot gas clouds (red) and huge smoke dust (yellow / orange) perpendicular to the narrow galaxy (white). Researchers used the Stratospheric Observatory for magnetic field data and infrared astronomy tools, which have been used extensively to study the physics around the Sun, to extrapolate the strength of the magnetic field in 20,000 light years around the galaxy. Like the sun’s solar wind, they seem to extend indefinitely into intergalactic space and can explain how gas and dust moved so far from the galaxy. Credits: NASA, SOFIA, L. Proudfit; NASA, ESA, Hubble Heritage Team; NASA, JPL-Caltech, C. Engelbracht
What is driving massive gas and dust emissions from the cigar galaxy also known as Messier 82?
We know that thousands of stars as they form drive a strong super wind that blows matter into intergalactic space. New research shows that magnetic fields also contribute to the ejection of material from Messier 82, a well-known example of a starburst galaxy with a characteristic, elongated shape.
The results of the Stratospheric Observatory for Infrared Astronomy (SOFIA) of NASA explain how dust and gas from galaxies can move into intergalactic space and give clues about the formation of galaxies. This material is enriched with elements like carbon and oxygen that support life and are the building blocks for future galaxies and stars. The research was presented at the American Astronomical Society meeting.
SOFIA, a joint project between NASA and the German Aerospace Center (DLR), previously investigated the direction of magnetic fields near the core of Messier 82, as the cigar galaxy is officially called. This time around, the team used tools that have been used extensively to study the physics around the sun, known as heliophysics, to understand the strength of the magnetic field that surrounds the galaxy at a distance ten times greater than before.
“This is old physics for studying the sun, but new for galaxies,” said Joan Schmelz, director of the Universities Space Research Association at NASA’s Ames Research Center in Silicon Valley and co-author of the upcoming paper on the research. “It helps us understand how the space between stars and galaxies became so rich in matter for future cosmic generations.”
Located 12 million light years from Earth in the constellation Ursa Major, the Cigar Galaxy is subject to an exceptionally high rate of star formation known as a starburst. The star formation is so intense that it creates a “super wind” that blows material out of the galaxy. As SOFIA previously determined with the instrumented high-resolution Airborne Wideband Camera (HAWC +), the wind pulls the magnetic field near the galaxy’s core in such a way that it runs perpendicular to the plane of the galaxy for over 2,000 light years.
The researchers wanted to find out whether the magnetic field lines, like the magnetic environment in the solar wind, extend indefinitely into intergalactic space or turn around to form structures that resemble similar coronal loops found in active regions of the sun. They calculate that the galaxy’s magnetic fields expand like the solar wind and that the material blown by the super wind can escape into intergalactic space.
These extended magnetic fields could explain how gas and dust discovered by space telescopes moved so far from the galaxy. NASA’s Spitzer Space Telescope detected dusty material 20,000 light-years behind the galaxy, but it was unclear why it had spread so far from the stars in both directions rather than in a cone-shaped beam.
“The magnetic fields may act like a freeway, creating trails for galactic material spreading far and wide into intergalactic space,” said Jordan Guerra Aguilera, postdoctoral fellow at Villanova University in Pennsylvania and co-author of the upcoming paper.
With rare exceptions, the magnetic field in the solar corona cannot be measured directly. About 50 years ago scientists developed methods for the accurate extrapolation of magnetic fields from the sun’s surface into interplanetary space, known in heliophysics as potential field extrapolation. Using SOFIA’s existing observations on central magnetic fields, the research team modified this method to estimate the magnetic field around 25,000 light years around the Cigar Galaxy.
“We can’t just measure the magnetic fields on such large scales, but we can extrapolate them from heliophysics with these tools,” said Enrique Lopez-Rodriguez, scientist with the Universities Space Research Association for SOFIA in Ames and lead author of the study. “This new, interdisciplinary method gives us the bigger perspective we need to understand starburst galaxies.”
SOFIA is a joint project between NASA and the German Aerospace Center. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science, and mission operations in collaboration with the Universities Space Research Association based in Columbia, Maryland, and the German SOFIA Institute at the University of Stuttgart. The aircraft is serviced and operated by NASA’s Armstrong Flight Research Center Building 703 in Palmdale, California. The high resolution broadband camera instrument in the air was developed and delivered to NASA by a team of several institutions under the direction of NASA’s Jet Propulsion Laboratory.
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