Sagittarius A* (Sgr A*), a supermassive black hole at the heart of our galaxy Milky Way, suddenly glowed brighter than its normal state becoming 75 times more luminescent before going back to its normal state. According to a team of astronomers who have been observing the black hole, it was at its brightest form measured in near-infrared wavelengths.
“I was pretty surprised at first and then very excited,” Tuan Do, an astronomer at the University of California Los Angeles told ScienceAlert. He further said that the black hole became so bright that he first mistook it to be star S0-2.
“Over the next few frames, though, it was clear the source was variable and had to be the black hole. I knew almost right away there was probably something interesting going on with the black hole,” the report said quoting Do.
He even took to Twitter to show a timelapse of images of how Sgr A* behaved during the said period in May earlier this year. Do and his team took the observations of the centre of the galaxy with the help of the WM Keck Observatory in Hawaii over four nights earlier this year and the unnatural brightening was seen on May 13.
Here’s a timelapse of images over 2.5 hr from May from @keckobservatory of the supermassive black hole Sgr A*. The black hole is always variable, but this was the brightest we’ve seen in the infrared so far. It was probably even brighter before we started observing that night! pic.twitter.com/MwXioZ7twV
— Tuan Do (@quantumpenguin) August 11, 2019
Scientists are on a mission to find out the reason which led to the unnatural brightening of Sgr A*. The findings so far are presently in press with The Astrophysical Journal Letters and is available on arXiv.
Black holes do not emit any radiation on their own that can be detected by our current instruments. However, the other objects that are nearby, do so when the gravitational forces of a black hole generate immense friction which in turn produces radiation.
According to the ScienceAlert report, there are two immediate possibilities, one is G2, which is thought to be a gas cloud, which approached within 36 light-hours of Sgr A* in 2014. Even if it was a gas cloud, the proximity should have torn it to shreds and some of it sucked in by the black hole, but nothing happened. It was later termed as a “cosmic fizzle”, however, the astronomers feel that the glowing of the black hole in May might have been a delayed reaction.
The other possibility according to Tuan Do, is the star S0-2, which had passed close to the black Hole last year, it may have changed the way gas flows into the Back Hole, so more gas is falling on it, leading it to become more variable, as per the report.
However, the only way to find out is by having more data, which is being collected across a larger range of wavelengths. There will be more observations in the coming weeks. The data may reveal different aspects of physics of the change in brightness, and help us understand what is happening to Sgr A*.
To recall, scientists had earlier this year also discovered the only space object – a lone star, that managed to escape the force of Sgr A* black hole. The news about the star which escaped the force of the black hole came a few months after astronomers across the world showed the first-ever image of a black hole.