The black hole of the Milky Way lights up suddenly and mysteriously



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The supermassive black hole in the center of the Milky Way is normally silent, but in May it surprised astronomers with an unprecedented explosion of infrared light.

On May 13th, the nearest supermassive black hole, called Sagittarius A *, or Sgr A *, was 75 times brighter than normal along the infrared region of the light spectrum, revealed a team of scientists.

According to a new article published Aug. 5 in arXiv, a scientific archive filing not yet reviewed by Cornell University, it is the most brilliant flash ever seen by scientists for 20 years, and twice more brilliant than any other. previously saved.

"The black hole was so bright that I first confused it with the star S0-2 because I had never seen Sgr A * as brilliant," said to ScienceAlert Tuan Do, astronomer and lead author of the document. "I knew almost immediately that there was probably something interesting with the black hole."

The new findings "push the boundaries of current statistical models" as they do not take into account such high levels of infrared flux and suggest that scientists understand that scientists misunderstand the central black hole of our galaxy. the paper.

The spiral of the Milky Way is centered 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 black "supermassive" hole at its center. The proximity of Sgr A * makes it the easiest black hole to study for scientists. The team that discovered this unprecedented outbreak observed Sgr A * for four nights with an infrared camera at the Keck Observatory of Mauna Kea in Hawaii.

They hoped to test Albert Einstein's theory of general relativity by observing how the black hole deformed the light of a nearby star. They have what they came for, plus the unprecedented infrared light.

Do not tweet a time frame of the event on Saturday.

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

"We think that something unusual may be happening this year, because the black hole seems to vary more in brightness, reaching levels brighter than ever before," said Do to Vice.

But researchers do not know exactly what is happening.

In black holes, the material is packed in a tiny space, which gives them an extremely powerful gravity – Sgr A *, for example, has a mass of 4 million suns. The force of attraction of a black hole is so strong that even the light can not escape. Researchers must therefore observe the infrared or X-rays that emanates from the black hole and interacts with gas and nearby stars.

The researchers think that such an interaction could have caused this luminous flash. More specifically, they said, an interaction with a near star passed near Sgr A * in 2018 could have disrupted the gas flows at the edge of the black hole handle.

They also pointed to a cloud of dust that passed near Sgr A * in 2014 but was not torn as dramatically as astronomers thought. The brightness could be a "delayed reaction", they wrote.

NASA's Chandra X-ray observatory captured an unprecedented Sagittarius A * X-ray rocket in 2013. This event was 400 times brighter than the usual x-ray output of the black hole.
NASA / CXC / Northwestern University / D.Haggard et al.

In 2013, scientists detected an equally mysterious X-ray eruption from Sgr A *, 400 times brighter than its normal X-ray levels.

Scientists should continue to monitor Sgr A * to see if he's undergoing any significant changes, the Do's team wrote. Other research could also be used to update models of the steady flow of black hole radiation levels.

"Many astronomers are watching Sgr A * this summer," Do told Vice. "I hope we can get as much data as possible this year before the sky region with Sgr A * sets in the sun and we can not see it before the year." next. "

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