XRISM clocks hot wind of galaxy M82 at 2 million mph
For the first time, astronomers have directly measured the speed of superheated gas billowing from a cauldron of stellar activity at the heart of M82, a nearby galaxy undergoing an extraordinary burst of star formation. The ...
Researchers made the calculations using data from the Resolve instrument aboard the XRISM (X-ray Imaging and Spectroscopy Mission) spacecraft.
"The classic model of starburst galaxies like M82 suggests that shock waves from star formation and supernovae near the center heat gas, kick-starting a powerful wind," said Erin Boettcher, an astrophysicist at the University of Maryland, College Park and NASA's Goddard Space Flight Center in Greenbelt, Maryland.
"Prior to XRISM, though, we didn't have the ability to measure the velocities needed to test that hypothesis. Now we see the gas moving even faster than some models predict, more than enough to drive the wind all the way to the edge of the galaxy."
A paper about the result, led by Boettcher, is published in Nature. The XRISM mission is led by JAXA (Japan Aerospace Exploration Agency) in collaboration with NASA, along with contributions from ESA (European Space Agency). NASA and JAXA also co-developed the Resolve instrument.
Sometimes called the Cigar galaxy, M82 is located 12 million light-years away in the northern constellation Ursa Major. Astronomers classify it as a starburst galaxy because it's forming stars at a much higher rate than typical for its size—about 10 times faster than the Milky Way.
The cool wind of galaxy M82 drives gas and dust up to 40,000 light-years from its core, as shown here using data from NASA’s Chandra X-ray Observatory and Hubble and Spitzer space telescopes. The inset shows a Chandra view of the galaxy’s central region, where a cauldron of stellar activity kick-starts the larger-scale outflow. Credit: NASA’s Goddard Space Flight Center; X-ray: NASA/CXC/JHU/D.Strickland; Optical: NASA/ESA/STScI/AURA/The Hubble Heritage Team; Infrared: NASA/JPL-Caltech/Univ. of AZ/C. Engelbracht; XRISM Collaboration et al. 2026
This image of M82, captured by the Near-Infrared Camera aboard NASA’s James Webb Space Telescope, shows the center of the galaxy in such detail that astronomers can distinguish small bright sources that are either individual stars or star clusters. NASA, ESA, CSA, STScI, Alberto Bolatto (UMD)
The Resolve instrument aboard the XRISM (X-ray Imaging and Spectroscopy Mission) spacecraft captured data revealing the velocity of the hot wind at the center of starburst galaxy M82. The energy range of iron emission lines show that the gas moves around 2 million miles (about 3 million kilometers) per hour. Inset: XRISM Xtend instrument’s image of M82. Credit: NASA’s Goddard Space Flight Center, JAXA/NASA, XRISM Collaboration et al. 2026