Supermassive black hole in our Galaxy’s centre turned mysteriously bright

Illustration of black hole with accretion disk

Illustration of black hole with accretion disk

This is pretty unusual, according to astronomers, since the Milky Way's black hole, Sagittarius A*, is tame and calm, and has pretty minimal fluctuations in brightness for as long as it has been observed.

Sagittarius A*, the central black hole of the Milky Way is regularly quite subdued, recorded activity levels being low over the course of the past years.

Supermassive black hole Sagittarius A* (Sgr A*) suddenly glowed way too brighter than its normal state in May earlier this year. He and his team observed this event when they were using the WM Keck Observatory in Hawaii and took a time-lapse of two hours.

S0-2 has been spotted a mere 17 light-hours away from the center as recently as previous year, and it's possible that the star's close relationship with the black hole has led to an increase in gas being swallowed up by it, which may have led to a burst of radiation visible using infrared. Black holes themselves don't emit any radiation that can be detected by our current instruments, but the stuff nearby does when the black hole's gravitational forces generate enormous friction, in turn producing radiation. The black hole is always variable, but this was the brightest we've seen in the infrared so far. Normally, the brightness of Sgr A* flickers a bit like a candle, varying from minutes to hours.

As a rule, if the environment of a black hole increases the brightness, this may indicate that something approached close enough to the hole and was captured by its gravity.

'The black hole was so bright I at first mistook it for the star S0-2, because I had never seen Sgr A* that bright. As ScienceAlert reports, the research team has a couple of possibilities in mind. There's also a gas cloud called G2 that swing around Sagittarius 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 produced a black hole.

But - have a look at the timelapse again. The visualization shows S0-2's close encounter with the black hole, as over a dozen other stars encircle Sagittarius A*. However, the objects and material close to them do-and changes to the black hole can excite matter nearby, allowing scientists to detect changes taking place.

Do told Science Alert, 'One of the possibilities, is that the star S0-2, when it passed close to the black hole a year ago, changed the way gas flows into the black hole, and so more gas is falling on it, leading it to become more variable'.

The only way to find out is having more data.

Currently, scientists are gathering as much information as they can.

Black holes have been extensively covered and studied over the past few decades with theory upon theory being stacked on one another, adding to the baffling enigma of this phenomena. The data may reveal different aspects of physics of the change in brightness, and help us understand what is happening to Sgr A*. The study is now available on a preprint website arXiv.