How the Milky Way stole a huge gas halo from our dwarf neighbors

Now, an international team of astronomers has found evidence that both Magellanic clouds are surrounded by massive hot haloes, which protect the gas stream from the Milky Way. Their new model has the largest mass in the gas stream.

Co-author of the study Professor Jose Bland-Hawthorne, Director University of Sydney Astronomy, Said: “We are lucky here in the Southern Hemisphere, to be able to see these nearby galaxies with the naked eye. We now know that these stellar smudges are surrounded by hot, gigantic, gaseous spheres.

“If humans can be seen in the intense violet and X-ray spectra, these remarkable structures can be seen emitting plasma throughout much of the night sky.”

Expired models

As scientists pull small galaxies under the influence of the Milky Way, parts of their halo expand and scatter to form the Magellanic Stream.

“The existing models for the formation of the Magellanic stream are out of date because they cannot calculate its mass,” said the lead author. Scott Luccini, Ph.D. student at the University of Wisconsin-Madison, USA.

His supervisor at Wisconsin-Madison, Professor Elena de Ongia, Said: “That’s why we came up with a new solution, which is great at explaining the mass of the stream.”

When older models opposed gravitational waves and the force of galaxies, dwarf galaxies orbited the Milky Way, creating the Magellanic Current. Although these models could explain the size and shape of the stream, they accounted for about one-tenth of its mass.

Recently, astronomers discovered that Magellanic clouds are large enough to have their own halo or corona. Professor de Ongia and his team realized that this would dramatically change how the corona stream formed.

“The stream is a 50-year-old puzzle,” said the co-author Dr. Andrew Fox, Astronomer at the Space Telescope Science Institute in Baltimore, USA, which operates the Hubble Space Telescope. “We never had a good explanation of where it came from. The most exciting thing is that we are now closing an explanation.”