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The black holes of the galaxy suddenly and mysteriously light up

The super-massive black hole in the middle of the Milky Way is normally quiet, but in May it surprised astronomers with an unprecedented explosion of infrared light.

The closest supermassive black hole to the earth, called Sagittarius A *, or Sgr A *, suddenly became 75 times brighter than normal along the near infrared area of ​​the light spectrum for two hours on May 13, found.

According to a new article they published August 5 in arXiv, a Cornell University archive for scientific articles that is not yet peer-reviewed, this was the brightest flash that researchers had seen in 20 years of observing the black hole – and twice as bright as anyone previously recorded.

"The black hole was so bright that I first mistook it for star S0-2, because I had never seen Sgr A * so bright," Tuan Do, an astronomer and lead author of the magazine, told ScienceAlert. "I knew almost immediately that there was probably something interesting about the black hole."

The new results "push the boundaries of current statistical models" because they do not account for infrared flow levels so high, and suggest that scientists' understanding of our galaxy's central black hole is not current, the team wrote in the magazine.

Milky Way's spiral centers around a supermassive black hole. Scientists believe that each galaxy has one at its center.
NASA / JPL-Caltech

Scientists believe that each galaxy has a particularly dense "supermassive" black hole in its center. The proximity to Sgr A * makes it the easiest black hole for researchers to study. The team that discovered this unmatched bloating observed Sgr A * for four nights with an infrared camera at the Keck Observatory at Mauna Kea, Hawaii.

They hoped to test Albert Einstein's theory of general relativity by observing how the black hole cast a nearby star's light. They got what they came for, plus the never before seen infrared flange.

You tweeted a time delay of the event on Saturday.

During three of the four observation nights, the black hole was in "a clearly elevated state," Do's team wrote.

"We think something unusual may happen this year because the black hole seems to vary in brightness more and reach lighter levels than we've ever seen before," Do.

But scientists are not sure what exactly is happening.

In black holes, matter is packed into a small space, giving them extremely powerful gravity – for example, Sgr A * has the mass of 4 million solar. The pull of a black hole is so strong that even light cannot escape, so scientists must observe the infrared light or X-rays that emit from the black hole and interact with nearby gas and stars.

The researchers believe that such an interaction could have caused this bright flash. More specifically, they said, an interaction with a nearby star that passed near Sgr A * in 2018 may have disturbed gas flows at the edge of the black hole's grip.

They also pointed to a dust cloud that passed near Sgr A * 2014 but did not dramatically break the way astronomers thought. The brightness can be a "delayed reaction," they wrote.

NASA's Chandra X-ray Observatory captured an unprecedented X-ray from Sagittarius A * 2013. This event was 400 times brighter than the usual X-ray output from the black hole.
NASA / CXC / Northwestern Univ / D.Haggard et al.

In 2013, researchers discovered an equally mysterious X-ray from Sgr A *, which was 400 times brighter than its normal levels of X-ray radiation.

Researchers should continue to monitor Sgr A * to see if it is experiencing significant changes, Do & # 39; s team wrote. More research can also be used to update models of the regular flow of the black hole's radiation levels.

"Many astronomers observe Sgr A * this summer," Do. "I hope we can get as much data as we can this year before the sky area with Sgr A * comes behind the sun and we will not be able to observe it again until next year."

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