Tammi Freehling | September 3, 2020
A team of scientists led by Nicolas Lehner, research professor at the University of Notre Dame, using NASA’s Hubble Space Telescope created a comprehensive map of the halo of plasma surrounding the Andromeda galaxy and discovered that it is already touching the halo of our own Milky Way.
The team’s findings, which appear in the Aug. 27 edition of The Astrophysical Journal, show that the Andromeda galaxy reaches about halfway to the Milky Way (about 1.3 million light-years) and in some directions extends for 2 million light-years.
The study also revealed the halo has a layered structure composed of two nested, distinct shells of gas.
“Understanding the huge halos of gas surrounding galaxies is immensely important,” explained Samantha Berek of Yale University, who is a Research Experience for Undergraduate summer student at Notre Dame. “This reservoir of gas contains fuel for future star formation within the galaxy, as well as outflows from events such as supernovae. It’s full of clues regarding the past and future evolution of the galaxy, and we’re finally able to study it in great detail in our closest galactic neighbor.”
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