The Large and Small Magellanic Clouds have been following a dangerous path for billions of years. As they are pulled in towards our home galaxy, they have begun to unraveling, leaving behind trail of debris. The dwarf galaxies are still intact with vigorous star formation.
The assistant professor at Colorado College said that a lot of people were trying to understand how the material could be there. How are they forming stars if this gas is gone?
With the help of data from NASA's Hubble Space Telescope and a retired satellite called the Far Ultraviolet Spectroscopic Explorer (FUSE), a team of astronomy led by Krishnarao has finally found the answer to the question, "Is the Magellanic system surrounded by a corona?" The two galaxies can continue to form new stars because of this.
The discovery was published in Nature. Andrew Fox of the Space Telescope Science Institute said thatGalaxies envelope themselves in gaseous cocoons, which act as defensive shields.
Several years ago, the corona's existence was predicted by an astronomer. Elena D'Onghia is a co-investigator at the University of Wisconsin–Madison. The Large Magellanic Cloud should have a corona.
Although the corona spans more than 100,000 light-years from the clouds, it is not visible to the naked eye. It needed to be mapped through 30 years of archives.
The primordial cloud of gas that collapsed to form the galaxy billions of years ago is thought to be the source of the corona. Astronomers had never before been able to look at a corona in such detail.
Krishnarao said observationally we can't really test most of the predictions because dwarf galaxies are too hard to detect. The Magellanic Clouds give us an ideal chance to study how dwarf galaxies interact.
The team combed through the archives of the Hubble and FUSE to look for evidence of the corona. Massive active black holes are found in quasars. Although the corona is too dim to see on its own, it should be visible as a fog obscuring bright light from quasars in the background. In the past, Hubble observations of quasars were used to map the corona.
The team was able to confirm the existence of the corona with the help of ultraviolet light from 28 quasars. The quasar's spectrum is imprinted with signatures of carbon, oxygen, and Silicon that make up the halo of hot plasma surrounding the galaxy.
The corona's ability to be detected required a lot of detail. Krishnarao said that the resolution of Hubble and FUSE was important for the study. The corona gas is very diffuse. It is mixed with other gases, including the streams from the Magellanic Clouds.
The team found that the amount of gas decreases with distance from the center. Krishnarao said it was a perfect telltale sign that the corona is real. It is protecting the universe.
There is a thin shroud of gas that protects a universe from destruction.
"Anything that tries to pass into the galaxy has to pass through this material first, so it can absorb some of that impact," said Krishnarao. The corona is the first material that can be taken apart. You're protecting the gas that's inside the galaxy itself and can form new stars by giving up some of the corona.
More information: Dhanesh Krishnarao et al, Observations of a Magellanic Corona, Nature (2022). DOI: 10.1038/s41586-022-05090-5 Journal information: Nature
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