![]() Krishnarao, D., Fox, A.J., D’Onghia, E.While giving up a little bit of the corona, you’re protecting the gas that’s inside of the galaxy itself and able to form new stars.” In addition, the corona is the first material that can be extracted. “Anything that tries to pass into the galaxy has to pass through this material first so that it can absorb some of that impact. It is cocooning the galaxy and protecting it.” It’s a perfect telltale signature that this corona is there. “By mapping the results, we also found that the amount of gas decreases with distance from the center of the Large Magellanic Cloud. In addition, it is mixed with other gases, including the streams pulled from the Magellanic Clouds and material originating in the Milky Way.” The corona gas is so diffuse it’s barely even there. The resolution of Hubble and FUSE were crucial for this study. Krishnarao said, “The ability to detect the corona required extremely detailed ultraviolet spectra. ![]() As expected, the distinctive traces of silicon, oxygen, and carbon that make up the halo of hot plasma surrounding the galaxy are etched on the quasar spectra. The team could identify and define the material encircling the Large Magellanic Cloud and establish that the corona exists by examining patterns in ultraviolet light from 28 quasars. Because they are right on our doorstep, the Magellanic Clouds provide an ideal opportunity to study how dwarf galaxies interact and evolve.” Krishnarao said, “There’re many predictions from computer simulations about what they should look like, how they should interact over billions of years, but observationally we can’t test most of them because dwarf galaxies are typically just too hard to detect. ![]() Despite the fact that coronas have been observed surrounding more distant dwarf galaxies, scientists have never been able to study one in such great detail. It required searching through 30 years of old data for appropriate metrics to map it out.Īccording to scientists, a galaxy’s corona is a piece of the original gas cloud that collapsed billions of years ago to create the galaxy. However, while covering a significant southern sky area and extending more than 100,000 light-years from the Magellanic clouds, the corona is essentially undetectable. We knew the Large Magellanic Cloud should be massive enough to have a corona.” We discovered that if we included a corona in the simulations of the Magellanic Clouds falling onto the Milky Way, we could explain the mass of extracted gas for the first time. Quasars have also been used to probe the Magellanic Stream, outflows from the Milky Way, and the halo surrounding the Andromeda Galaxy.Įlena D’Onghia, a co-investigator at the University of Wisconsin–Madison, said, “Astronomers predicted the corona’s existence several years ago. This study used archival observations of quasars from Hubble’s Cosmic Origins Spectrograph (COS) and the Far Ultraviolet Spectroscopic Explorer (FUSE). Because each quasar probes a different part of the corona, the research team was also able to show that the amount of gas decreases with distance from the center of the Large Magellanic Cloud. The quasar spectra become imprinted with the distinct signatures of carbon, oxygen, and silicon ions that make up the corona gas. As the quasar light passes through the corona, certain wavelengths (colors) of ultraviolet light are absorbed. The detection of the Magellanic Corona was made by analyzing patterns in ultraviolet light from 28 distant background quasars. The corona is thought to act as a buffer protecting the dwarf galaxies’ vital star-forming gas from the gravitational pull of the much larger Milky Way. This journey has begun to unravel what were once barred spirals with multiple arms into more irregular-shaped galaxies with long tails of debris. The Magellanic Clouds, dwarf galaxies roughly 160,000 light-years from Earth, are the largest of the Milky Way’s satellites and are thought to be on their first in-falling passage around the Milky Way. Shown here in purple, the corona stretches more than 100,000 light-years from the main mass of stars, gas, and dust that make up the Magellanic Clouds, intermingling with the hotter and more extensive corona that surrounds the Milky Way. ![]() Researchers have used spectroscopic observations of ultraviolet light from quasars to detect and map out the Magellanic Corona, a diffuse halo of hot, supercharged gas surrounding the Small and Large Magellanic Clouds.
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