Paris, France:

Astronomers have been able to observe a supermassive black hole waking up and setting the heart of its host galaxy alight for the first time, the European Southern Observatory said on Tuesday.

The galaxy 300 million light years from Earth in the Virgo constellation had been quiet for decades until late 2019, when it suddenly began to shine brighter than ever before.

The centre of the galaxy — where a supermassive black hole is believed to be squatting — since then has been radiating a variety of rays. 

“This behaviour is unprecedented,” Paula Sanchez Saez, an European Southern Observatory astronomer and first author of a new study in the journal Astronomy & Astrophysics, said in a statement.

The “most tangible option” to explain this brightening is that the astronomers were watching “the activation of a massive black hole in real time”, study co-author Lorena Hernandez Garcia said.

Most galaxies — including our own Milky Way — are believed to have a supermassive black hole at their centre.

These cosmic behemoths are by definition invisible — not even light can escape the pull of their awesome power.

The only way to observe black holes is when they destroy something huge that lets off light in its death throes: such as a star that wandered too close being torn apart.

“These giant monsters usually are sleeping,” study co-author Claudio Ricci explained.

But for the galaxy SDSS1335+0728, “we were able to observe the awakening of the massive black hole, (which) suddenly started to feast on gas available in its surroundings, becoming very bright,” the astrophysicist added.

Initial observations indicate the black hole has 1.5 million times more mass than the Sun, enough for it to be classified as a supermassive black hole. 

But it is still on the lighter side, as the true heavyweights easily exceed a billion times the Sun’s mass.

The international team of astronomers is analysing data from a number of telescopes hoping to determine whether the black hole’s activity is temporary — perhaps caused by a star being ripped apart — or whether it will continue to be active for a long time. 

“This is something that could happen also to our own Sgr A*,” the Milky Way’s supermassive black hole, Hernandez Garcia said.

But fortunately for us, our own black hole remains fast asleep.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

The interaction between a supermassive black hole in a galaxy named 2MASX J02301709+2836050 and a star orbiting it is seen in this image captured by the Pan-STARRS telescope, in Hawaii, U.S., in an undated handout image provided by NASA.
| Photo Credit: Reuters

Black holes, celestial objects known for their gluttony, usually eat stars unlucky enough to stray too close to them in one big gulp, annihilating them with their enormous gravitational pull. But some, it turns out, tend to snack rather than gorge.

Researchers said they have observed a supermassive black hole at the center of a relatively nearby galaxy as it takes bites out of a star similar in size and composition to our sun, consuming material equal to about three times Earth’s mass each time the star makes a close pass on its elongated oval-shaped obit.

Black holes are extraordinarily dense objects with gravity so strong that not even light can escape.

The star is located about 520 million light years from our solar system. A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). It was observed being plundered by a supermassive black hole at the heart of a spiral-shaped galaxy.

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As such black holes go, this one is relatively small, estimated to have a mass a few hundred thousand times larger than the sun. The supermassive black hole at the center of our galaxy, called Sagittarius A*, possesses about 4 million times the mass of our sun. Some other galaxies harbor supermassive black holes hundreds of millions times the mass of the sun.

Most galaxies have such black holes at their center, and the environment around them can be among the most violent places in the universe.

Most of the data used by the scientists in the new study came from NASA’s orbiting Neil Gehrels Swift Observatory.

The star was observed orbiting the black hole every 20 to 30 days. At one end of its orbit, it ventures near enough to the black hole to have some material from its stellar atmosphere sucked away, or accreted, each time it passes – but not so close as to have the whole star shredded. Such an event is called a “repeating partial tidal disruption.”

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The stellar material that falls into the black hole heats up to around 3.6 million degrees Fahrenheit (2 million degrees Celsius), unleashing an immense amount of X-rays. Those were detected by the space observatory.

“What’s most likely to happen is the star’s orbit will gradually decay and it will get closer and closer to the supermassive black hole until it gets close enough to be completely disrupted,” said astrophysicist Rob Eyles-Ferris of the University of Leicester in England, one of the authors of the study published this week in the journal Nature Astronomy.

“That process is likely to take years at least – more likely decades or centuries,” Eyles-Ferris added.

This marked the first time that scientists had observed a sun-like star being repeatedly snacked upon by a supermassive black hole.

“There are lots of unanswered questions about tidal disruption events and exactly how the orbit of the star affects them,” Eyles-Ferris said. “It’s a very fast-moving field at the moment. This one has shown us that new discoveries could come at any time.”