Hubble detects a protective shield defending a pair of dwarf galaxies

The iconic Hubble Space Telescope has made numerous discoveries during its three-decade career.

Now he may have solved another mystery: how the Milky Way’s two largest satellite galaxies remain intact and are capable of forming stars.

The phenomenon has long baffled astronomers because, for billions of years, the Large and Small Magellanic Clouds have been breaking up and leaving trails of gaseous debris as they orbit each other and are drawn toward our home galaxy. .

However, despite this, dwarf galaxies can still create stellar material when they would not be expected to have enough gas to do so.

Thanks to the Hubble data, the answer to the puzzle appears to lie in the fact that the Magellanic system is surrounded by a protective shield of supercharged hot gas called the corona.

Theory: Hubble may have discovered how the Large and Small Magellanic Clouds can form stars despite leaving trails of gaseous debris.  The system is surrounded by a protective shield of hot gas that prevents its gas supplies from being siphoned off by the Milky Way.

Theory: Hubble may have discovered how the Large and Small Magellanic Clouds can form stars despite leaving trails of gaseous debris. The system is surrounded by a protective shield of hot gas that prevents its gas supplies from being siphoned off by the Milky Way.

MAGALAN CLOUDS: SATELLITE GALAXIES FOR THE MILKY WAY

The Magellanic Clouds can be seen in the night sky with the naked eye and have been observed by ancient cultures for thousands of years.

The Large Magellanic Cloud is a relatively small distance of 160,000 light-years from us, while the Small Magellanic Cloud is about 200,000 light-years away.

They orbit the Milky Way once every 1.5 billion years and each other once every 900 million years.

They were the closest known galaxies to the Milky Way until recently, when the Sagittarius and Canis Major dwarf galaxies were discovered and found to be even closer.

This engulfs the two dwarf galaxies, preventing the neighboring Milky Way from siphoning off their supplies of gas, and thus allowing them to continue forming new stars.

“A lot of people were struggling to explain how these material flows could be there,” said Dhanesh Krishnarao, an assistant professor at Colorado College.

‘If this gas was removed from these galaxies, how come they are still forming stars?’

He and his team found out why with the help of Hubble and a retired satellite called the Far Ultraviolet Spectroscopic Explorer (FUSE).

“Galaxies wrap themselves in gaseous cocoons, which act as defensive shields against other galaxies,” said co-investigator Andrew Fox of the Space Telescope Science Institute in Baltimore, Maryland.

Astronomers predicted the existence of the corona several years ago.

“We found that if we included a corona in simulations of the Magellanic Clouds falling on the Milky Way, we could explain the mass of gas extracted for the first time,” said Elena D’Onghia, a co-investigator at the University of Wisconsin–Madison.

“We knew that the Large Magellanic Cloud should be massive enough to have a corona.”

Although the corona extends more than 100,000 light-years from the Magellanic clouds and covers much of the southern sky, it is practically invisible.

Mapping it meant astronomers had to search through 30 years of archived data to get proper measurements.

They think that the corona of a galaxy is a remnant of the primordial cloud of gas that collapsed to form the galaxy billions of years ago.

Although coronae have been seen around more distant dwarf galaxies, astronomers have never before been able to probe one in as much detail as this.

“There are a lot of predictions from computer simulations about how they should look like, how they should interact over billions of years, but by looking, we can’t really test most of them because dwarf galaxies are usually too hard to detect,” he said. Krishnarao.

Although the corona extends more than 100,000 light-years from the Magellanic clouds and covers much of the southern sky, it is practically invisible.

Although the corona extends more than 100,000 light-years from the Magellanic clouds and covers much of the southern sky, it is practically invisible.

Although the corona extends more than 100,000 light-years from the Magellanic clouds and covers much of the southern sky, it is practically invisible.

Because they are right around the corner, the Magellanic Clouds provide an ideal opportunity to study how dwarf galaxies interact and evolve.

Searching for direct evidence of Magellan’s Corona, the team combed through the Hubble and FUSE archives for ultraviolet observations of quasars located billions of light-years behind it.

Quasars are the extremely bright nuclei of galaxies that are home to huge, active black holes.

The team theorized that although the corona would be too faint to be seen on its own, it should be visible as a kind of fog that obscures and absorbs distinct patterns of bright light from quasars in the background.

Hubble observations of quasars were used in the past to map the corona surrounding the Andromeda galaxy.

By analyzing patterns in ultraviolet light from 28 quasars, the team was able to detect and characterize the material surrounding the Large Magellanic Cloud and confirm that the corona exists.

The Hubble Space Telescope (pictured) has been observing the universe for more than 30 years.

The Hubble Space Telescope (pictured) has been observing the universe for more than 30 years.

The Hubble Space Telescope (pictured) has been observing the universe for more than 30 years.

As predicted, the quasar’s spectra are imprinted with the distinct signatures of carbon, oxygen, and silicon that make up the halo of hot plasma that surrounds the galaxy.

The ability to detect the corona required extremely detailed ultraviolet spectra.

“The resolution of Hubble and FUSE were crucial to this study,” said Krishnarao. “The corona gas is so diffuse, it’s barely there.”

Additionally, it mixes with other gases, including streams drawn from the Magellanic Clouds and material originating from the Milky Way.

By mapping the results, the team also found that the amount of gas decreases with distance from the center of the Large Magellanic Cloud.

“It’s a perfect telltale signature that this crown is really there,” Krishnarao said. “It’s really engulfing the galaxy and protecting it.”

So how can such a thin shell of gas protect a galaxy 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,” Krishnarao said.

“In addition, the crown is the first material that can be extracted. While giving up a bit of the corona, you are protecting the gas that is within the galaxy itself and capable of forming new stars.’

The discovery has been published in the journal Nature.

NASA’s Hubble Space Telescope is still operating and has made more than 1.5 million observations since its mission began in 1990.

The Hubble Telescope was launched on April 24, 1990 via the space shuttle Discovery from the Kennedy Space Center in Florida.

It is named after the famous astronomer Edwin Hubble, who was born in Missouri in 1889.

He is arguably most famous for discovering that the universe is expanding and the rate at which it is expanding, now known as the Hubble constant.

The Hubble Telescope is named after the famous astronomer Edwin Hubble, who was born in Missouri in 1889 (pictured)

The Hubble Telescope is named after the famous astronomer Edwin Hubble, who was born in Missouri in 1889 (pictured)

The Hubble Telescope is named after the famous astronomer Edwin Hubble, who was born in Missouri in 1889 (pictured)

Hubble has made more than 1.5 million observations since its mission began in 1990 and helped publish some 18,000 scientific papers.

It circles the Earth at a speed of about 17,000 mph (27,300 kph) in low Earth orbit at about 340 miles in altitude.

Hubble has a pointing accuracy of 0.007 arcseconds, which is like being able to shine a focused laser beam on Franklin D. Roosevelt’s head on a dime from about 200 miles (320 km) away.

The Hubble Telescope is named after Edwin Hubble, who was responsible for finding the Hubble constant and is one of the greatest astronomers of all time.

The Hubble Telescope is named after Edwin Hubble, who was responsible for finding the Hubble constant and is one of the greatest astronomers of all time.

The Hubble Telescope is named after Edwin Hubble, who was responsible for finding the Hubble constant and is one of the greatest astronomers of all time.

Hubble’s main mirror is 2.4 meters (7 feet, 10.5 inches) wide and a total of 13.3 meters (43.5 feet) long, the length of a large school bus.

The launch and deployment of Hubble in April 1990 marked the most significant advance in astronomy since Galileo’s telescope.

Thanks to five service missions and more than 25 years of operation, our vision of the universe and our place within it has never been the same.

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